If the kinetic energy of the particle is increased to 16 times its previous value, the percentage change in the de-Broglie wavelength of the particle is:
1. 25
2. 75
3. 60
4. 50
For photoelectric emission from certain metals, the cutoff frequency is . If radiation of frequency 2 impinges on the metal plate, the maximum possible velocity of the emitted electron will be:
(m is the electron mass)
1.
2.
3.
4.
A 200 W sodium street lamp emits yellow light of wavelength 0.6 . Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is:
1.
2.
3.
4.
An -particle moves in a circular path of radius 0.83 cm in the presence of a magnetic field of 0.25 Wb/m2. The de-Broglie wavelength associated with the particle will be:
A radioactive nucleus of mass M emits a photon of frequency and the nucleus will recoil. The recoil energy will be:
1.
2. zero
3.
4.
1. 1.3 V
2. 0.5 V
3. 2.3 V
4. 1.8 V
1. 1:2
2. 1:1
3. 1:5
4. 1:4
1. decrease by 2 times
2. decrease by 4 times
3. increase by 4 times
4. increase by 2 times
A source S1 is producing 1015 photons per sec of wavelength 5000 Å. Another source S2 is producing 1.02×1015 photons per second of wavelength 5100 Å. Then, (power of S2)/(power of S1) is equal to:
1. 1.00
2. 1.02
3. 1.04
4. 0.98