- The saturation photocurrent remains almost the same.
- The maximum kinetic energy of the photoelectrons is doubled.
- Both A and Bare true.
- A is true but B is false.
- A is false but B is true.
- Both A and B are false.
Explanation:
Saturated current varies directly with the intensity of light. As the intensity of light is increased, a large number of photons fall on the metal surface. As a result, a large number of electrons interact with the photons. As a result, the number of emitted electrons increases and, hence, the current also increases.
At the same time, the frequency of the light source also increases.Also, with the increase in frequency of light, the stopping potential increases as well. This will reduce the current. The combined effect of these two is that the current will remain the same. Hence, A is true.
From the Einstein's photoelectric equation.
$\text{K}_\text{max}= \text{hv}-\varphi$
Where Kmax = kinetic energy of electron
v = frequency of light
$\varphi$ = work function of metal
It is clear from the above equation. As the frequency of light source is doubled, kinetic energy of electron increases. But, it becomes more than the double.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
$\overrightarrow{\text{F}}.\overrightarrow{\text{a}}$
$\overrightarrow{\text{v}}.\overrightarrow{\text{r}}$
$\overrightarrow{\text{a}}.\overrightarrow{\text{r}}$
$\overrightarrow{\text{F}}.\overrightarrow{\text{r}}$
To obtain P-type Si semiconductor, we need to dope pure Si with
|
(a) Aluminium |
(b) Phosphorous |
(c) Oxygen |
(d) Germanium |
A condenser having a capacity 2.0 micro farad is charged to 200 volts and then the plates of the capacitor are connected to a resistance wire. The heat produced in joules will be
|
(a) 4 |
(b) 4 |
(c) 4 |
(d) 2 |
The count rate of a Geiger- Muller counter for the radiation of a radioactive material of half life of 30 minutes decreases to 5
after 2 hours. The initial count rate was
|
(a) 25 |
(b) 80 |
(c) 625 |
(d) 20 |
The valence of the impurity atom that is to be added to germanium crystal so as to make it a N-type semiconductor, is
|
(a) 6 |
(b) 5 |
(c) 4 |
(d) 3 |
A radioactive sample with a half life of 1 month has the label : “Activity=2 micro curies on 1.8.1991.'' What will be its activity two months later
|
(a) 1.0 micro curies |
(b) 0.5 micro curies |
(c) 4 micro curies |
(d) 8 micro curies |
Field inside a solenoid is
|
(a) Directly proportional to its length |
|
(b) Directly proportional to current |
|
(c) Inversely proportional to total number of turns |
|
(d) Inversely proportional to current |