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
1. ultraviolet region.
2. visible region.
3. infrared region.
4. X-ray region.
1. | excitation of electrons in the atoms |
2. | a collision between the atoms of the gas |
3. | collisions between the charged particles emitted from the cathode and the atoms of the gas |
4. | a collision between different electrons of the atoms of the gas |
A 5 W emits monochromatic light of wavelength 5000 Å. When placed 0.5 m away, it liberates photoelectrons from a photosensitive metallic surface. When the source is moved 1.0 m away, the number of photoelectrons liberated is reduced by a factor of?
1. 4
2. 8
3.16
4. 2
Monochromatic light of frequency 6.0×1014 Hz is produced by a laser. The power emitted is 2×10-3 W. The number of photons emitted, on average, by the source per second is:
1.
2.
3.
4.