G-MS2D75B7RR

# Worksheet on Dual Nature, Atoms & Nuclei

Q1 The energy of photon of visible light with maximum wavelength in eV is :

a) 1

b) 1.6

c) 3.2

d) 7

Q2 The strength of photoelectric current is directly proportional to :

a) Frequency of incident radiation

b) Intensity of incident radiation

c) Angle of incidence of radiation

d) Distance between anode and cathode

Q3 When light is incident on surface, photo electrons are emitted. For photoelectrons :

a) The value of kinetic energy is same for

b) Maximum kinetic energy do not depend on the wave length of incident light

c) The value of kinetic energy is equal to or less than a maximum kinetic energy

d) None of the above.

Q4 When light falls on a photosensitive surface, electrons are emitted from the surface. The kinetic energy of these electrons does not depend on the :

a) Wavelength of light

b) Frequency of light

c) Type of material used for the surface

d) Intensity of light

Q5 The work-function of a substance is 4.0 eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately :

a) 450 nm

b) 400 nm

c) 310 nm

d) 220 nm

Q6 Which one among shows particle nature of light.

a) P.E.E.

b) Interference

c) Refraction

d) Polarization

Q7 According to Einstein’s photoelectric equation, the plot of the kinetic energy of the emitted photoelectrons from a metal v/s the frequency of the incident radiation gives a straight line whose slope :

a) Depends on the intensity of the radiation

b) Depends of the nature of the metal used

c) Depends both on the intensity of the radiation and the metal used.

d) Is the same for all metals and independent of the intensity of the radiation.

Q8 The De Broglie wavelength of an electron in the first bohr orbit is :

a) Equal to the circumference of the first orbit

b) Equal to twice the circumference of the first orbit

c) Equal to half the circumference of the first orbit.

d) Equal to one fourth the circumference of first orbit

Q9 A photo-cell employs photoelectric effect to convert.

a) Change in the frequency of light into a change in electric voltage

b) Change in the intensity of illumination into a change in photoelectric current

c) Change in the intensity of illumination into a change in the work function of the photocathode

d) Change in the frequency of light into a change in the electric current

Q10 Assertion :- Photoelectric effect demonstrates the wave nature of light.

Reason :-The number of photo electrons is properties to the frequency of light.

a) A

b) B

c) C

d) D

Q11 Assertion :- A photon is not a material particle. It is a quanta of energy.

Reason :- Photoelectric effect demonstrate wave nature of radiation.

a) A

b) B

c) C

d) D

Q12 Assertion :- Among the particles of same kinetic energy; lighter particle has greater de Broglie wavelength.

Reason :-The de-Broglie wavelength of a particle depends only on the charge of the particle.

a) A

b) B

c) C

d) D

Q13 Assertion :- Speed of light is independent of frame of reference.

Reason :- Speed of light is the ultimate speed of particle.

a) A

b) B

c) C

d) D

Q14 As the mass number increases, binding energy per nucleon :-

a) Increases

b) decreases

c) remains same

d) may increase or may decrease

Q15 Possible forces on a proton by a proton in a nucleus is/are :-

a) Coulomb force

b) Nuclear

c) Gravitational force

d) All of these

Q16 Energy is released in nuclear fission is due to.

(a) Few mass is converted into energy

(b) Total binding energy of fragments is more than the B.E. of parental element

(c) Total B.E. of fragments is less than the B.E. of parental element

(d) Total B.E. of fragments is equals to the B.E. of parental element is

a) a,c

b) a,b

c) a,d

d) All

Q17 Energy in an atom bomb is produced by the process of :

a) nuclear fusion

b) nuclear fission

c) combination of hydrogen atoms

d) combination of electrons and protons

Q18 Which of the following is weakest force :-

a) Gravitational force

b) Electric force

c) Magnetic force

d) Nuclear force

Q19 Neutrino is a particle, which is :

a) charged like an electron and has no spin

b) chargeless and has spin

c) chargeless and has no spin

d) charged like an electron and has spin

Q20 Which of the following statement is incorrect :-

a) Nuclear forces are always attractive

b) Nuclear force are stronger than Colombian force at distance of femtometer

c) Nuclear force are repulsive at distance less than 0.8 femtometer

d) Nuclear forces are spin dependent

Q21 Assertion :- A heavy nucleus may also undergo fission to give two fission fragments.

Reason :- A heavy nucleus has a smaller coulomb force.

a) A

b) B

c) C

d) D

Q22 Assertion :- Heavy nuclei are highly unstable.

Reason :- In heavy nuclei, neutrons are much greater than protons.

a) A

b) B

c) C

d) D

Q23 Assertion :- X-rays are high energy photons.

Reason :- -particles are helium nuclei.

a) A

b) B

c) C

d) D

Q24 Assertion :- Soft and hard X-rays differ in frequency only.

Reason :- Hard X-rays propagate at higher speed than soft X-rays.

a) A

b) B

c) C

d) D

1) b

2) b

3) c

4) d

5) c

6) a

7) d

8) a

9) b

10) d

11) c

12) c

13) b

14) d

15) d

16) b

17) b

18) a

19) b

20) a

21) c

22) b

23) b

24) c