Modern Physics Class 12 MCQ: Class 12 Physics MCQ Questions and Answer. Students get here all Important MCQ on Modern Physics Class 12.
Modern Physics Class 12 MCQ with Answers:
Multiple choice questions.
1) According to special theory of relativity, time is not absolute quantity. It depends upon the motion of the________
a) Relativity.
b) Frame of reference.
c) Observer.
d) Light
Ans : b) Frame of reference
2.) If t be the time dilation and t0 be the proper time,v be the uniform velocity and c be the speed of light then time delation can be expressed as
4.) m0 be the rest mass of the object and E be the energy and m be the mass of the object then energy mass relation can be expressed as.
a) E0=mc².
b) E=(m0-m)c²
c) E=m0c².
d) E0=m0c²
Ans : d) E0=m0c²
5.) m0 be the rest mass of the object and m be the mass of the object then kinetic energy can be expressed as.
a) K.E=mc².
b) K.E=(m0-m)c²
c) K.E=(m-m0)c²
d) K.E=m0c²
Ans : c) K.E=(m-m0)c²
6.) The relation between change in mass and change in energy can be expressed as.
a)∆m = ∆E/c²
b) ∆E = ∆m/c²
c) ∆m = ∆E/ mc²
d) ∆E = ∆m / mc²
Ans : a) ∆m = ∆E/c²
7.) T be the given temperature,the emitted energy has maximum value for a certain wavelength λmax then the product of λmax×T is
a) zero.
b) constant
c) one.
d) infinite
Ans : b) constant
8.) The value of Wien’s constant is
a)2.9×10-3 mK
b) 1.9×10-8 mK
c) 2.8×10-9 m-1K-1
d) 1.8×10-3 mK
Ans : a) 2.9×10-3 mK
9.) E = σT⁴
The above relation is known as.
a) Lentz law.
b) Stefan-Boltzmann law
c) Planck’s law.
d) Wien’s law
Ans : b) Stefan – Boltzmann law.
10.) E be the energy ,h be the Planck’s constant and f be the frequency then the relation between them is,
a)E = hf.
b) f = Eh
c) h = Ef.
d) f = √Eh
Ans : a) E = hf
11.) The value of Planck’s constant is
a)6.63×10-36 ms.
b) 6.63×10-34
c) 6.63×10-36 ms-2.
d) 6.63×10-32
Ans : b) 6.63×10-34 Js
12.) The value of Stefan’s constant
a)5.67×10-12 Wm-1K-4
b) 5.67×10-3 Wm-2K-1
c) 5.67×10-8 Wm-4K-4
d) 5.67×10-8 Wm-2K-4
Ans : d) 5.67×10-8 Wm-2K-4
13.) If λ be the wave length of beam of light, h be the Planck’s constant and from the theory of relativity momentum p of the photon is related to energy then it can be written as.
a) p = h/λ.
b) p = h /λ²
c) p = hλ.
d) p = h/√λ
Ans : a) p = h/λ
14.) The emission of electrons from a metal surface when exposed to light of suitable frequency is called.
a) Lentz effect.
b) Photoelectric effect
c) Relativity effect.
d) Planck’s effect
Ans : b) Photoelectric effect
15.) The maximum energy of photoelectrons can be written as
½mv²max = ____
a)V0e.
b) hV²
c) Vm².
d) ½ mh
Ans : a) V0e
16.) Fill in the blank.
Incident photo energy – Work function = _________
a) Max. P.E. of photoelectron
b) Max. K.E. of photoelectron
c) Min. P.E. of photoelectron
d) Max. K.E. of photoelectron
Ans : b) Max. K.E. of photoelectron
17.) Complete the Einstein’s photoelectric equation. hf – Φ=_____
a)½mV²max
b) phf
c) hΦmin.
d) hfm²max
Ans : a)½mV²max
18.) If fo be the threshold frequency and h be the Planck’s constant, when K.E of the photoelectron is zero then then the work function is,
a)Φ= hfo.
b)Φ= hfo/2
c) Φ= 1/hfo.
d) Φ= h-fo
Ans : a) Φ= hfo
19.) Einstein’s photoelectric equation for maximum kinetic energy is, K.Emax =____
a)hf+hfo
b) hf-hfo
c) hfo-hf
d)hf/hfo
Ans : b) hf-hfo
20.) Fill in the blank.
The change in wavelength ∆λ know as Compton shift for scattering angle θ.
λ =(h/moc)(_____)
a) cosθ.
b)sinθ
c) 1- cosθ.
d) 1- sinθ
Ans : c) 1- cosθ
21.) The value of Compton wavelength is
(h/moc) = _____
a) 2.83×10-2
b) 4.43×10-12m-2
c) 3.43×10-32m-1
d) 2.43×10-12m
Ans : d) 2.43×10-12m
22.) If λ be the wavelength associated with particle wave, m be the mass and h be the Planck’s constant and v be the velocity then relation between them is,
a) λ = h/mv
b) λ = hm/v
c) λ = hv/m
d) λ = mv/h
Ans : a) λ = h/mv
23.) A particle of madd 7mg moves with speed of 10 ms-1.its de Broglie wavelength is ,
a) 2.183×10-28
b) 1.183×10-29m
c) 1.183×10-28
d) 2.183×10-30
Ans : b) 1.183×10-29 m.
24.) An electron is accelerated through a potential difference of 55 V. Its de Broglie wavelength is,
a) 0.165×10-12
b) 1.65×10-9m
c) 1.05×10-11
d) 1.65×10-10m
Ans : d) 1.65×10-10m
25.) Fill in the blank.
“The product of the uncertainty ∆x in the position of a particle at some instant and the uncertainty ∆p in the x- component of its momentum at the same instant approximately equal ______”
a.) Lentz constant
b) Boltzmann constant kB
c) Planck’s constant h
d) Wien’s constant.
Ans : c) Planck’s constant h
26.) Complete the formula of uncertainty principle.
∆E.___ ≈ h
a) p/2π.
b) ∆t
c) ∆c².
d) ∆m²
Ans : b) ∆t
27.) The change of very high energy photon into an electron, positron pair is called,
a) Pair reduction.
b) Pair production
c) annihilation of matter.
d) annihilation of photon
Ans : b) Pair production
28.) When a positron comes close to an electron, they annihilation and produce two photons in the γ-rays range. It is called,
a) Pair reduction.
b) Pair production
c) annihilation of matter.
d) annihilation of photon
Ans : c) annihilation of matter.
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