Physics questions and answers
PART I
1. Who is known as the father of physics?
Galileo Galilei
2. Who discovered the law of gravitation?
Isaac Newton
3. Unit of force?
Newton (N)
4. Unit of energy?
Joule (J)
5. Unit of power?
Watt (W)
6. Unit of electric current?
Ampere (A)
7. Unit of resistance?
Ohm (Ω)
8. Unit of potential difference?
Volt (V)
9. Unit of frequency?
Hertz (Hz)
10. Unit of pressure?
Pascal (Pa)
11. SI unit of temperature?
Kelvin (K)
12. Who discovered electron?
J.J. Thomson
13. Who discovered X-rays?
Wilhelm Roentgen
14. Who discovered radioactivity?
Henri Becquerel
15. Who discovered proton?
Goldstein
16. Who discovered neutron?
James Chadwick
17. Speed of light in vacuum?
3 × 10⁸ m/s
18. Speed of sound in air (approx.)?
343 m/s
19. Value of acceleration due to gravity (g) on Earth?
9.8 m/s²
20. Unit of work?
Joule (J)
21. Work done when displacement is zero?
Zero
22. Energy possessed due to motion?
Kinetic energy
23. Energy possessed due to position or configuration?
Potential energy
24. Law of conservation of energy states?
Energy can neither be created nor destroyed; it only changes form.
25. Instrument used to measure current?
Ammeter
26. Instrument used to measure potential difference?
Voltmeter
27. Instrument used to measure resistance?
Ohmmeter
28. Instrument used to measure power of electric circuit?
Wattmeter
29. Instrument used to measure atmospheric pressure?
Barometer
30. Instrument used to measure temperature?
Thermometer
31. Instrument used to measure humidity?
Hygrometer
32. Instrument used to measure intensity of earthquakes?
Seismograph
33. Instrument used to measure speed of wind?
Anemometer
34. Instrument used to measure very high temperature?
Pyrometer
35. Instrument used to measure electric charge?
Electrometer
36. Who gave the theory of relativity?
Albert Einstein
37. Who is known as the father of modern physics?
Albert Einstein
38. Who is known as the father of nuclear physics?
Ernest Rutherford
39. Who is known as the father of modern science?
Galileo Galilei
40. Which law explains why we wear seat belts?
Newton’s First Law (Law of Inertia)
41. Which law states action and reaction are equal and opposite?
Newton’s Third Law
42. Which law gives F = ma?
Newton’s Second Law
43. What is the SI unit of momentum?
kg·m/s
44. Momentum = ?
Mass × Velocity
45. Force = ?
Mass × Acceleration
46. Work = ?
Force × Displacement (in the direction of force)
47. Power = ?
Work / Time
48. Energy stored in a stretched spring is?
Elastic potential energy
49. SI unit of heat?
Joule (J)
50. Unit of sound intensity?
Decibel (dB)
51. Speed of light in glass?
Approximately 2 × 10⁸ m/s
52. Refractive index of water?
1.33
53. Refractive index of glass?
1.5
54. Unit of electric field?
N/C (Newton per Coulomb)
55. Electric field = ?
Force / Charge
56. Unit of electric potential?
Volt (V)
57. Electric potential = ?
Work done / Charge
58. Ohm’s law states?
Current through a conductor is directly proportional to voltage across it, at constant temperature
59. Unit of capacitance?
Farad (F)
60. Capacitance = ?
Charge / Potential difference
61. Unit of magnetic field?
Tesla (T)
62. Magnetic field B = ?
Force / (Charge × Velocity)
63. SI unit of inductance?
Henry (H)
64. Inductance = ?
Induced EMF / Rate of change of current
65. Unit of frequency?
Hertz (Hz)
66. Frequency = ?
1 / Time period
67. Unit of wavelength?
Meter (m)
68. Wave speed = ?
Frequency × Wavelength
69. Light year = ?
Distance travelled by light in one year (~9.46 × 10¹² km)
70. Reflection of light follows which laws?
Laws of reflection: 1) Angle of incidence = Angle of reflection 2) Incident ray, reflected ray, and normal lie in same plane
71. Refraction occurs due to?
Change in speed of light in different medium
72. Total internal reflection occurs when?
Light moves from denser to rarer medium and angle of incidence > critical angle
73. Critical angle for water–air interface?
48.6°
74. Lens formula?
1/f = 1/v – 1/u
75. Magnification = ?
Image height / Object height
76. Power of a lens = ?
100 / Focal length (in cm)
77. Convex lens is also called?
Converging lens
78. Concave lens is also called?
Diverging lens
79. Unit of luminous intensity?
Candela (cd)
80. Speed of sound in air?
343 m/s
81. Doppler effect explains?
Change in frequency due to relative motion of source and observer
82. Unit of work?
Joule (J)
83. Work done = ?
Force × Displacement × cosθ
84. Unit of power?
Watt (W)
85. Kinetic energy = ?
½ mv²
86. Potential energy = ?
mgh
87. Law of conservation of energy states?
Energy can neither be created nor destroyed; only converted
88. Elastic collision preserves?
Both momentum and kinetic energy
89. Inelastic collision preserves?
Momentum only
90. Unit of momentum?
kg·m/s
91. Momentum = ?
Mass × Velocity
92. Impulse = ?
Change in momentum
93. Gravitational potential energy = ?
mgh
94. Acceleration due to gravity = ?
9.8 m/s²
95. Escape velocity = ?
√(2GM/R)
96. Kepler’s first law?
Planet moves in elliptical orbit with sun at one focus
97. Kepler’s second law?
Radius vector sweeps equal areas in equal time
98. Kepler’s third law?
T² ∝ r³
99. Unit of electric charge?
Coulomb (C)
100. Charge of one electron?
1.6 × 10⁻¹⁹ C
Part II
101. Unit of work?
Joule (J)
102. Work = ?
Force × Displacement × cosθ
103. Unit of power?
Watt (W)
104. Power = ?
Work / Time
105. Kinetic energy = ?
½ mv²
106. Potential energy = ?
mgh
107. Law of conservation of energy states?
Energy can neither be created nor destroyed, only converted
108. Elastic collision preserves?
Both momentum and kinetic energy
109. Inelastic collision preserves?
Momentum only
110. Momentum = ?
Mass × Velocity
111. Impulse = ?
Change in momentum
112. Gravitational potential energy = ?
mgh
113. Acceleration due to gravity on Earth?
9.8 m/s²
114. Escape velocity = ?
√(2GM/R)
115. Kepler’s first law?
Planet moves in elliptical orbit with Sun at one focus
116. Kepler’s second law?
Radius vector sweeps equal areas in equal time
117. Kepler’s third law?
T² ∝ r³
118. Work done when displacement is zero?
Zero
119. Unit of pressure?
Pascal (Pa)
120. Pressure = ?
Force / Area
121. Unit of density?
kg/m³
122. Density = ?
Mass / Volume
123. Unit of acceleration?
m/s²
124. Acceleration = ?
(Final velocity – Initial velocity) / Time
125. Unit of velocity?
m/s
126. Velocity = ?
Displacement / Time
127. Average velocity = ?
Total displacement / Total time
128. Acceleration due to gravity on Moon?
1.62 m/s²
129. SI unit of gravitational constant (G)?
N·m²/kg²
130. Newton’s first law of motion?
Law of inertia: A body remains at rest or in uniform motion unless acted upon by a force
131. Newton’s second law of motion?
F = ma
132. Newton’s third law of motion?
Action and reaction are equal and opposite
133. Unit of force?
Newton (N)
134. 1 Newton = ?
1 kg·m/s²
135. Unit of work?
Joule (J)
136. 1 Joule = ?
1 N·m
137. Unit of power?
Watt (W)
138. 1 Watt = ?
1 J/s
139. Energy possessed due to motion?
Kinetic energy
140. Energy possessed due to position?
Potential energy
141. Mechanical energy = ?
Kinetic energy + Potential energy
142. Elastic potential energy = ?
½ kx²
143. Work done by a conservative force is?
Independent of path
144. Work done by non-conservative force?
Depends on path
145. Unit of momentum?
kg·m/s
146. Impulse = ?
Change in momentum
147. Law of conservation of linear momentum?
Total momentum remains constant if no external force acts
148. Simple harmonic motion is?
Motion where restoring force ∝ displacement
149. Frequency of SHM = ?
1 / Time period
150. Time period of SHM = ?
2π √(m/k) for mass-spring system
151. Time period of a simple pendulum = ?
T = 2π √(l/g)
152. Frequency of simple pendulum = ?
1 / T
153. Unit of angular velocity?
rad/s
154. Angular velocity = ?
θ / t
155. Centripetal force = ?
mv² / r
156. Centripetal acceleration = ?
v² / r
157. Unit of torque?
N·m
158. Torque = ?
Force × Perpendicular distance
159. Work done by torque = ?
Torque × Angular displacement
160. Power in rotational motion = ?
Torque × Angular velocity
161. Unit of moment of inertia?
kg·m²
162. Moment of inertia = ?
Σ m r²
163. Unit of angular momentum?
kg·m²/s
164. Angular momentum = ?
Moment of inertia × Angular velocity
165. Unit of surface tension?
N/m
166. Surface tension = ?
Force / Length
167. Capillary rise = ?
2T cosθ / (ρ g r)
168. Pressure difference across curved surface = ?
2T / r
169. Unit of viscosity?
Pa·s
170. Stoke’s law?
F = 6πηrv
171. Unit of frequency?
Hertz (Hz)
172. Wave speed = ?
Frequency × Wavelength
173. Refractive index = ?
Speed of light in vacuum / Speed of light in medium
174. Critical angle = ?
sin⁻¹(1/n)
175. Total internal reflection occurs when?
Light moves from denser to rarer medium and angle of incidence > critical angle
176. Lens formula?
1/f = 1/v – 1/u
177. Magnification = ?
Image height / Object height
178. Power of a lens = ?
100 / Focal length (in cm)
179. Convex lens is also called?
Converging lens
180. Concave lens is also called?
Diverging lens
181. Focal length of concave mirror is?
Negative, f = -R/2
182. Focal length of convex mirror is?
Positive, f = R/2
183. Lateral magnification of mirror = ?
Image height / Object height = -v/u
184. Unit of luminous intensity?
Candela (cd)
185. Illuminance = ?
Luminous flux / Area
186. Unit of illuminance?
Lux (lx)
187. Reflection follows which laws?
1) Angle of incidence = Angle of reflection 2) Incident ray, reflected ray, and normal lie in same plane
188. Refraction occurs due to?
Change in speed of light in different medium
189. Refractive index of a medium = ?
sin i / sin r
190. Total internal reflection occurs when?
Angle of incidence > Critical angle, light from denser to rarer medium
191. Critical angle for water–air interface?
48.6°
192. Speed of light in vacuum?
3 × 10⁸ m/s
193. Speed of light in glass?
2 × 10⁸ m/s (approx)
194. Doppler effect explains?
Change in frequency due to relative motion of source and observer
195. Unit of charge?
Coulomb (C)
196. Charge of one electron?
1.6 × 10⁻¹⁹ C
197. Ohm’s law states?
Current through conductor ∝ Voltage at constant temperature
198. Capacitance = ?
Charge / Potential difference
199. Inductance = ?
Induced EMF / Rate of change of current
200. Unit of magnetic field?
Tesla (T)
Part III
201. Unit of work?
Joule (J)
202. Work done = ?
Force × Displacement × cosθ
203. Unit of power?
Watt (W)
204. Power = ?
Work / Time
205. Kinetic energy = ?
½ mv²
206. Potential energy = ?
mgh
207. Law of conservation of energy states?
Total energy remains constant
208. Impulse = ?
Force × Time
209. Momentum = ?
Mass × Velocity
210. Newton’s first law states?
A body remains at rest or in uniform motion unless acted upon by external force
211. Newton’s second law states?
F = ma
212. Newton’s third law states?
Action = Reaction
213. Pressure = ?
Force / Area
214. Unit of pressure?
Pascal (Pa)
215. Archimedes’ principle states?
Upthrust = Weight of fluid displaced
216. Buoyant force acts in which direction?
Upward
217. Density = ?
Mass / Volume
218. Specific gravity = ?
Density of substance / Density of water
219. Hydraulic press works on which principle?
Pascal’s principle
220. Work done in lifting a body = ?
Weight × Height
221. Mechanical advantage = ?
Load / Effort
222. Efficiency = ?
(Mechanical advantage / Velocity ratio) × 100
223. Unit of frequency?
Hertz (Hz)
224. Wave velocity = ?
Frequency × Wavelength
225. Sound requires medium for
propagation?
Yes
226. Speed of sound in air?
343 m/s (at 25°C)
227. Unit of wavelength?
Meter (m)
228. Frequency range of audible sound?
20 Hz – 20 kHz
229. Ultrasound frequency range?
>20 kHz
230. Infrasound frequency range?
<20 Hz
231. Doppler effect occurs due to?
Relative motion between source and observer
232. Pitch of sound depends on?
Frequency
233. Loudness of sound depends on?
Amplitude
234. Echo is?
Reflection of sound
235. Reverberation is?
Persistence of sound due to multiple reflections
236. Unit of electric current?
Ampere (A)
237. Unit of charge?
Coulomb (C)
238. Unit of resistance?
Ohm (Ω)
239. Ohm’s law?
V = IR
240. Resistivity = ?
Resistance × (Area / Length)
241. Series combination of resistors: R = ?
R₁ + R₂ + R₃ …
242. Parallel combination of resistors: 1/R = ?
1/R₁ + 1/R₂ + 1/R₃ …
243. Kirchhoff’s first law?
Sum of currents at a junction = 0
244. Kirchhoff’s second law?
Sum of voltage in a closed loop = 0
245. Potential difference across a conductor = ?
Current × Resistance
246. Power dissipated in resistor = ?
I²R or VI
247. Capacitance = ?
Charge / Potential difference (C = Q/V)
248. Unit of capacitance?
Farad (F)
249. Energy stored in capacitor = ?
½ CV²
250. Dielectric increases which property of capacitor?
Capacitance
251. Unit of magnetic field (B)?
Tesla (T)
252. Magnetic field around a long straight current-carrying wire?
B = μ₀I / 2πr
253. Magnetic force on moving charge?
F = q(v × B)
254. Magnetic force on current-carrying conductor?
F = BIL sinθ
255. Right-hand rule is used for?
Direction of magnetic field around current
256. Ampere’s circuital law states?
∮B·dl = μ₀I_enclosed
257. Unit of magnetic moment?
A·m²
258. Torque on a current loop in magnetic field = ?
τ = μ × B
259. Faraday’s law of electromagnetic induction?
Induced emf = –dΦ/dt
260. Lenz’s law states?
Induced current opposes the change causing it
261. Self-inductance = ?
L = NΦ / I
262. Unit of inductance?
Henry (H)
263. Energy stored in inductor = ?
½ LI²
264. AC frequency in India?
50 Hz
265. RMS value of AC = ?
I_rms = I₀/√2
266. Peak value of AC = ?
I₀ = √2 × I_rms
267. Impedance in AC circuit = ?
Z = √(R² + (X_L – X_C)²)
268. Resonance occurs when?
X_L = X_C
269. Time period of simple harmonic motion = ?
T = 2π√(m/k)
270. Frequency of simple harmonic motion = ?
f = 1/T
271. Maximum velocity in SHM = ?
ωA
272. Maximum acceleration in SHM = ?
ω²A
273. Potential energy in SHM = ?
½ k x²
274. Kinetic energy in SHM = ?
½ k(A² – x²)
275. Total energy in SHM = ?
½ k A² (constant)
276. Hooke’s law states?
F = kx
277. Potential energy stored in a spring = ?
½ kx²
278. Oscillation of a spring-mass system: Time period = ?
T = 2π√(m/k)
279. Simple pendulum: Time period = ?
T = 2π√(l/g)
280. Gravitational potential energy = ?
U = –G(m₁m₂/r)
281. Escape velocity from Earth = ?
v = √(2GM/R)
282. Orbital velocity of satellite = ?
v = √(GM/R)
283. Kepler’s first law?
Planet moves in elliptical orbit with Sun at one focus
284. Kepler’s second law?
Line joining Sun and planet sweeps equal areas in equal time
285. Kepler’s third law?
T² ∝ r³
286. Gravitational constant = ?
G = 6.67 × 10⁻¹¹ N·m²/kg²
287. Unit of work done = ?
Joule (J)
288. Unit of energy = ?
Joule (J)
289. Unit of power = ?
Watt (W)
290. Efficiency = ?
(Useful energy output / Total energy input) × 100
291. Law of conservation of linear momentum states?
Total momentum before = Total momentum after
292. Impulse-momentum theorem?
Impulse = Change in momentum
293. Centripetal acceleration = ?
a = v²/r
294. Centripetal force = ?
F = mv²/r
295. Angular velocity = ?
ω = θ / t
296. Relation between linear and angular velocity?
v = rω
297. Rotational kinetic energy = ?
½ Iω²
298. Torque = ?
τ = r × F
299. Moment of inertia of solid sphere = ?
I = 2/5 MR²
300. Moment of inertia of hollow sphere = ?
I = 2/3 MR²
Part IV
301. Speed of light in vacuum?
3 × 10⁸ m/s
302. Unit of electric charge?
Coulomb (C)
303. Unit of electric current?
Ampere (A)
304. Unit of potential difference?
Volt (V)
305. Unit of resistance?
Ohm (Ω)
306. Unit of capacitance?
Farad (F)
307. Unit of magnetic field?
Tesla (T)
308. Unit of inductance?
Henry (H)
309. Ohm’s law states?
V = IR
310. Series combination of resistors: R = ?
R₁ + R₂ + R₃ …
311. Parallel combination of resistors: 1/R = ?
1/R₁ + 1/R₂ + 1/R₃ …
312. Current in parallel branches?
I_total = I₁ + I₂ + I₃ …
313. Power dissipated in resistor = ?
P = I²R or VI
314. Capacitance = ?
C = Q/V
315. Energy stored in capacitor = ?
½ CV²
316. Dielectric increases which property of capacitor?
Capacitance
317. Magnetic force on moving charge?
F = q(v × B)
318. Magnetic force on current-carrying conductor?
F = BIL sinθ
319. Faraday’s law of electromagnetic induction?
Induced emf = –dΦ/dt
320. Lenz’s law states?
Induced current opposes the change causing it
321. Self-inductance = ?
L = NΦ / I
322. Energy stored in inductor = ?
½ LI²
323. AC frequency in India?
50 Hz
324. RMS value of AC = ?
I_rms = I₀/√2
325. Peak value of AC = ?
I₀ = √2 × I_rms
326. Impedance in AC circuit = ?
Z = √(R² + (X_L – X_C)²)
327. Reactance of inductor = ?
X_L = 2πfL
328. Reactance of capacitor = ?
X_C = 1 / (2πfC)
329. Resonance occurs when?
X_L = X_C
330. Time period of simple harmonic motion = ?
T = 2π√(m/k)
331. Frequency of SHM = ?
f = 1/T
332. Maximum velocity in SHM = ?
v_max = ωA
333. Maximum acceleration in SHM = ?
a_max = ω²A
334. Potential energy in SHM = ?
½ k x²
335. Kinetic energy in SHM = ?
½ k(A² – x²)
336. Total energy in SHM = ?
½ k A² (constant)
337. Hooke’s law states?
F = kx
338. Potential energy stored in spring = ?
½ kx²
339. Time period of spring-mass system = ?
T = 2π√(m/k)
340. Time period of simple pendulum = ?
T = 2π√(l/g)
341. Gravitational potential energy = ?
U = –G(m₁m₂/r)
342. Escape velocity from Earth = ?
v = √(2GM/R)
343. Orbital velocity of satellite = ?
v = √(GM/R)
344. Kepler’s first law?
Planet moves in elliptical orbit with Sun at one focus
345. Kepler’s second law?
Line joining Sun and planet sweeps equal areas in equal time
346. Kepler’s third law?
T² ∝ r³
347. Gravitational constant = ?
G = 6.67 × 10⁻¹¹ N·m²/kg²
348. Law of conservation of linear momentum states?
Total momentum before = Total momentum after
349. Impulse-momentum theorem?
Impulse = Change in momentum
350. Centripetal acceleration = ?
a = v²/r
351. Centripetal force formula?
F = mv²/r
352. Centripetal acceleration = ?
a = v²/r
353. Angular velocity = ?
ω = θ / t
354. Relation between linear and angular velocity?
v = rω
355. Rotational kinetic energy = ?
½ Iω²
356. Torque = ?
τ = r × F
357. Moment of inertia of solid sphere = ?
I = 2/5 MR²
358. Moment of inertia of hollow sphere = ?
I = 2/3 MR²
359. Moment of inertia of solid cylinder = ?
I = ½ MR²
360. Moment of inertia of hollow cylinder = ?
I = MR²
361. Angular momentum = ?
L = Iω
362. Law of conservation of angular momentum?
L_initial = L_final
363. Precession of a gyroscope occurs due to?
Torque acting on it
364. Unit of angular momentum?
kg·m²/s
365. Unit of torque?
N·m
366. Unit of moment of inertia?
kg·m²
367. Rotational work = ?
τ × θ
368. Rotational power = ?
τ × ω
369. Kinetic energy of rolling object = ?
Translational + Rotational = ½ mv² + ½ Iω²
370. Equilibrium condition in rotation?
Στ = 0, ΣF = 0
371. Simple harmonic motion: Time period = ?
T = 2π√(m/k)
372. Frequency of SHM = ?
f = 1/T
373. Maximum velocity in SHM = ?
v_max = ωA
374. Maximum acceleration in SHM = ?
a_max = ω²A
375. Total energy in SHM = ?
½ k A²
376. Wave equation?
v = fλ
377. Frequency = ?
f = 1/T
378. Time period = ?
T = 1/f
379. Speed of sound in air?
343 m/s (at 25°C)
380. Speed of light in vacuum?
3 × 10⁸ m/s
381. Refractive index = ?
n = c/v
382. Snell’s law?
n₁ sinθ₁ = n₂ sinθ₂
383. Critical angle = ?
θ_c = sin⁻¹(n₂/n₁)
384. Total internal reflection occurs when?
θ > θ_c and light goes from denser to rarer medium
385. Lens formula?
1/f = 1/v – 1/u
386. Magnification?
m = v/u
387. Power of lens?
P = 100/f (f in cm)
388. Convex lens forms real image when object is?
Beyond F (focus)
389. Concave lens forms image?
Virtual, erect, diminished
390. Mirror formula?
1/f = 1/v + 1/u
391. Concave mirror forms real image when object is?
Beyond F (focus)
392. Convex mirror forms image?
Virtual, erect, diminished
393. Magnification of mirror = ?
m = –v/u
394. Focal length of concave mirror is positive or negative?
Negative
395. Focal length of convex mirror is positive or negative?
Positive
396. Lens power for convex lens?
Positive
397. Lens power for concave lens?
Negative
398. Dispersion of light occurs due to?
Refraction
399. Prism formula?
μ = sin((A+D_m)/2)/sin(A/2)
400. Deviation is minimum when?
Light passes symmetrically through prism
401. Newton’s first law of motion states?
A body continues in its state of rest or uniform motion unless acted upon by a net external force
402. Newton’s second law of motion?
F = ma
403. Newton’s third law of motion?
Action = –Reaction
404. Work done = ?
W = F·d·cosθ
405. Unit of work?
Joule (J)
406. Power = ?
P = W/t
407. Unit of power?
Watt (W)
408. Kinetic energy = ?
KE = ½ mv²
409. Potential energy = ?
PE = mgh
410. Mechanical energy = ?
E = KE + PE
411. Law of conservation of energy states?
Total energy of an isolated system remains constant
412. Momentum = ?
p = mv
413. Impulse = ?
J = F·t
414. Impulse-momentum theorem?
Impulse = Change in momentum
415. Gravitational force = ?
F = G(m₁m₂/r²)
416. Acceleration due to gravity (g) = ?
g = 9.8 m/s²
417. Escape velocity = ?
v = √(2GM/R)
418. Orbital velocity of satellite = ?
v = √(GM/R)
419. Hooke’s law?
F = kx
420. Stress = ?
Force/Area
421. Strain = ?
ΔL/L
422. Young’s modulus = ?
Stress/Strain
423. Bulk modulus = ?
ΔP / (–ΔV/V)
424. Shear modulus = ?
Stress / Shear strain
425. Surface tension unit?
N/m
426. Surface tension = ?
Force per unit length (N/m)
427. Capillary rise formula?
h = 2Tcosθ / (ρgr)
428. Viscosity unit?
Pa·s or N·s/m²
429. Stokes’ law?
F = 6πηrv
430. Rate of flow of liquid (Poiseuille’s equation)?
Q = πPr⁴ / 8ηl
431. Bernoulli’s principle?
P + ½ ρv² + ρgh = constant
432. Work function?
Minimum energy to remove an electron from metal surface
433. Photoelectric effect equation?
hf = φ + ½ mv²
434. Einstein’s photoelectric equation?
K.E. = hf – φ
435. De Broglie wavelength?
λ = h/p
436. Heisenberg uncertainty principle?
Δx·Δp ≥ h/4π
437. Bohr’s radius?
5.29 × 10⁻¹¹ m
438. Energy of electron in nth orbit (Hydrogen atom)?
E_n = –13.6/n² eV
439. Rydberg formula?
1/λ = R(1/n₁² – 1/n₂²)
440. Magnetic force on moving charge?
F = q(v × B)
441. Lorentz force?
F = q(E + v × B)
442. Magnetic dipole moment?
μ = I·A
443. Torque on a magnetic dipole?
τ = μ × B
444. Potential energy of magnetic dipole?
U = –μ·B
445. Current in a conductor = ?
I = Q/t
446. Ohm’s law?
V = IR
447. Resistivity unit?
Ω·m
448. Series resistance?
R = R₁ + R₂ + …
449. Parallel resistance?
1/R = 1/R₁ + 1/R₂ + …
450. Power in electrical circuit?
P = VI = I²R = V²/R
451. Coulomb’s law?
F = k(q₁q₂/r²)
452. Unit of electric charge?
Coulomb (C)
453. Unit of electric field?
N/C or V/m
454. Electric field due to point charge?
E = kq/r²
455. Electric potential energy?
U = k(q₁q₂/r)
456. Electric potential?
V = kq/r
457. Relation between E and V?
E = –dV/dr
458. Capacitance definition?
C = Q/V
459. Unit of capacitance?
Farad (F)
460. Energy stored in capacitor?
U = ½ CV²
461. Series capacitance?
1/C = 1/C₁ + 1/C₂ + …
462. Parallel capacitance?
C = C₁ + C₂ + …
463. Current (I) definition?
Rate of flow of charge, I = Q/t
464. Ohm’s law?
V = IR
465. Resistance unit?
Ohm (Ω)
466. Resistivity definition?
ρ = R·A/L
467. Series resistance?
R = R₁ + R₂ + …
468. Parallel resistance?
1/R = 1/R₁ + 1/R₂ + …
469. Kirchhoff’s first law?
Sum of currents at a junction = 0
470. Kirchhoff’s second law?
Sum of EMF in a loop = Sum of voltage drops
471. Magnetic field around straight conductor?
B = μ₀I/2πr
472. Force on current-carrying wire in magnetic field?
F = BIL sinθ
473. Force on moving charge in magnetic field?
F = q(v × B)
474. Magnetic flux?
Φ = B·A·cosθ
475. Faraday’s law of electromagnetic induction?
Induced EMF ∝ Rate of change of magnetic flux
476. Lenz’s law?
Induced current opposes the change causing it
477. Self-inductance (L) definition?
L = Induced EMF / Rate of change of current
478. Unit of inductance?
Henry (H)
479. Energy stored in inductor?
U = ½ LI²
480. Mutual inductance (M) definition?
EMF induced in one coil due to change of current in another
481. AC frequency in India?
50 Hz
482. AC voltage formula?
V = V₀ sin ωt
483. AC current formula?
I = I₀ sin ωt
484. Root mean square (RMS) voltage?
V_rms = V₀/√2
485. Root mean square (RMS) current?
I_rms = I₀/√2
486. Reactance of capacitor (Xc)?
Xc = 1/2πfC
487. Reactance of inductor (Xl)?
Xl = 2πfL
488. Impedance in series LCR circuit?
Z = √(R² + (Xl – Xc)²)
489. Resonance in LCR circuit occurs when?
Xl = Xc
490. Resonant frequency?
f₀ = 1 / 2π√(LC)
491. Transformer formula?
Vp/Vs = Np/Ns
492. Step-up transformer?
Vs > Vp
493. Step-down transformer?
Vs < Vp
494. Efficiency of transformer?
η = (Ps/Pp) × 100%
495. Electromagnetic waves travel at?
3 × 10⁸ m/s in vacuum
496. Speed of light in vacuum?
3 × 10⁸ m/s
497. Reflection law?
Angle of incidence = Angle of reflection
498. Refraction law?
n₁ sinθ₁ = n₂ sinθ₂
499. Total internal reflection occurs when?
Light passes from denser to rarer medium and θ > θc
500. Critical angle definition?
Angle of incidence in denser medium for which angle of refraction = 90°
Part VI
501. Work done formula?
W = F × d × cosθ
502. Kinetic energy formula?
KE = ½ mv²
503. Potential energy formula?
PE = mgh
504. Power formula?
P = W/t = F·v
505. Mechanical advantage (MA) definition?
MA = Load / Effort
506. Velocity formula?
v = d/t
507. Acceleration formula?
a = Δv / t
508. Newton’s first law?
Law of inertia
509. Newton’s second law?
F = ma
510. Newton’s third law?
Action = –Reaction
511. Impulse formula?
J = FΔt = Δp
512. Momentum formula?
p = mv
513. Conservation of momentum?
Total momentum before = Total momentum after
514. Gravitational force formula?
F = G m₁m₂ / r²
515. Acceleration due to gravity (g)?
g = GM / R²
516. Work-Energy theorem?
W = ΔKE
517. Power in terms of force and velocity?
P = F·v
518. Hooke’s law?
F = kx
519. Elastic potential energy?
U = ½ kx²
520. Simple harmonic motion displacement?
x = A sin(ωt + φ)
521. Frequency and period relation?
f = 1/T
522. Angular frequency?
ω = 2πf
523. Velocity in SHM?
v = ω√(A² – x²)
524. Acceleration in SHM?
a = –ω²x
525. Restoring force in SHM?
F = –kx
526. Simple pendulum period formula?
T = 2π√(L/g)
527. Length of pendulum (L) formula?
L = gT² / 4π²
528. Maximum speed in SHM?
vmax = ωA
529. Maximum acceleration in SHM?
amax = ω²A
530. Work done in one cycle of SHM?
0
531. Energy in SHM?
E = ½ kA² = KE + PE
532. Transverse wave?
Oscillation perpendicular to propagation
533. Longitudinal wave?
Oscillation parallel to propagation
534. Wave velocity formula?
v = fλ
535. Frequency formula?
f = 1/T
536. Sound speed in air?
~343 m/s at 25°C
537. Intensity of sound formula?
I = P/A
538. Decibel level formula?
β = 10 log(I/I₀)
539. Doppler effect formula?
f’ = f(v ± vo)/(v ∓ vs)
540. Reflection law?
Angle of incidence = Angle of reflection
541. Refraction law (Snell’s law)?
n₁ sinθ₁ = n₂ sinθ₂
542. Critical angle definition?
Angle of incidence for which refracted ray = 90°
543. Total internal reflection condition?
n₁ > n₂ and θ > θc
544. Lens formula?
1/f = 1/v – 1/u
545. Magnification formula?
m = h’/h = v/u
546. Power of lens formula?
P = 100 / f (f in cm)
547. Mirror formula?
1/f = 1/v + 1/u
548. Concave mirror image type?
Real or virtual depending on object distance
549. Convex mirror image type?
Always virtual, erect, diminished
550. Refractive index definition?
n = c/v
Mechanics
- Work: W = F·d·cosθ; KE = ½mv²; PE = mgh
- Power: P = W/t = F·v; Momentum: p = mv; Impulse: J = Δp
- Newton’s Laws: F = ma; Action = –Reaction
- Gravity: F = G m₁m₂/r²; g = GM/R²
SHM & Waves
- Pendulum: T = 2π√(L/g)
- SHM: x = A sin(ωt + φ); vmax = ωA; amax = ω²A
- Energy: E = KE + PE = ½kA²
- Wave: v = fλ; Transverse: ⟂ oscillation; Longitudinal: ∥ oscillation
Optics
- Reflection: θi = θr; Refraction: n₁ sinθ₁ = n₂ sinθ₂
- Lens formula: 1/f = 1/v – 1/u; Magnification: m = v/u
- Concave mirror → real/virtual; Convex mirror → always virtual
Sound & Doppler
- Speed of sound: ~343 m/s (air)
- Intensity: I = P/A; Decibel: β = 10 log(I/I₀)
- Doppler effect: f’ = f(v ± vo)/(v ∓ vs)
