Dual Nature of Radiation and Matter

A photoemissive substance is illuminated with a radiation of wavelength i so that it releases electrons with de-Broglie wavelength e. The longest wavelength of radiation that can emit photoelectron is o. Expression for de-Broglie wavelength is given by: (m: mass of the electron, h: Planck's constant and c: speed of light)

1. e = h i 2mc
2. e = h 2mc ( 1 i - 1 o )
3. e = h2mc ( 1 i - 1 o )
4. e = h o2mc

A small mirror of mass m is suspended by a massless thread of length l. Then the small angle through which the thread will be deflected when a short pulse of laser of energy E falls normal on the mirror (c = speed of light in vacuum and g = acceleration due to gravity)

1. = Emc gl
2. = E2mc gl
3. = 3E4mc gl
4. = 2Emc gl

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R In the light of the above statements, choose the correct answer from the options given below

1. Both A and R are true and R is the correct explanation of A
2. A is false but R is true
3. Both A and R are true but R is NOT the correct explanation of A
4. A is true but R is false

The work function of a metal is 3 eV. The color of the visible light that is required to cause emission of photoelectrons is

1. Red
2. Green
3. Blue
4. Yellow

If and K are de Broglie wavelength and kinetic energy, respectively, of a particle with constant mass, the correct graphical representation for the particle will be :

1. [figure]
2. [figure]
3. [figure]
4. [figure]

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the most appropriate answer from the options given below :

1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is false but (R) is true
4. (A) is true but (R) is false

In an experiment with photoelectric effect, the stopping potential,

1. is ( 1e ) times the maximum kinetic energy of the emitted photoelectrons
2. increases with increase in the intensity of the incident light
3. decreases with increase in the intensity of the incident light
4. increases with increase in the wavelength of the incident light

A proton of mass 'mp' has same energy 'E' as that of a photon of wavelength ' '. If the proton is moving at non-relativistic speed, then ratio of its de Broglie wavelength to the wavelength of photon is

1. 1c Emp
2. 1c 2Emp
3. 12c Emp
4. 1c E2mp

Which of the following phenomena cannot be explained by wave theory of light?

1. Refraction of light
2. Reflection of light
3. Diffraction of light
4. Compton effect

An electron of mass 'm' with an initial velocity v=v0 i (v0>0) enters an electric field E=-Eo k. If the initial de Broglie wavelength is 0, the value after time t would be

1. o 1- e2Eo2t2m2vo2
2. 0
3. o 1+ e2Eo2t2m2vo2
4. o 1+ e2Eo2t2m2vo2