The figure shows different graphs between stopping potential and frequency (\(\nu\)) for the photosensitive surfaces of cesium, potassium, sodium and lithium. The plots are parallel.
The correct ranking of the targets according to their work function first will be:
1. (i) > (ii) > (iii) > (iv)
2. (i) > (iii) > (ii) > (iv)
3. (iv) > (iii) > (ii) > (i)
4. (i) = (iii) > (ii) = (iv)
The collector plate in an experiment on the photoelectric effect is kept vertically above the emitter plate. A light source is put on and a saturation photocurrent is recorded. When an electric field is switched on that has a vertically downward direction, then:
1. the photocurrent will increase.
2. the kinetic energy of the electrons will increase.
3. the stopping potential will decrease.
4. the threshold wavelength will increase.
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. ultraviolet region.
2. visible region.
3. infrared region.
4. X-ray region.
|1.||Curves a and b represent incident radiations of different frequencies and different intensities.|
|2.||Curves a and b represent incident radiation of the same frequency but of different intensities.|
|3.||Curves b and c represent incident radiation of different frequencies and different intensities.|
|4.||Curves b and c represent incident radiations of same frequency having the same intensity.|
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)
When the light of frequency \(2\nu_0\) (where \(\nu_0\) is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is v1. When the frequency of the incident radiation is increased to \(5\nu_0,\) the maximum velocity of electrons emitted from the same plate is v2. What will be the ratio of v1 to v2?
1. 1 : 2
2. 1 : 4
3. 4 : 1
4. 2 : 1
An electron of mass m with an initial velocity \((v_o>0)\) enters in an electric field (Eo = constant>0) at t=0. If , is its de-Broglie wavelength initially, then what will be its de-Broglie wavelength at time t?
The photoelectric threshold wavelength of silver is 3250 x 10-10 m. What will be the velocity of the electron ejected from a silver surface by the ultraviolet light of wavelength 2536 x 10-10 m?
(Given h= and )
4. \(\approx 0.3\times 10^5\) ms-1