Consider the experimental set-up of verification of photoelectric effect shown in the figure. The voltage across the electrodes is measured with the help of an ideal voltmeter and which can be varied by moving jockey J on the potentiometer wire. The battery used in potentiometer circuit is of 20 V and its internal resistance is $2 Ω$ . The resistance of 100 cm along potentiometer wire is $8 Ω$ .
The photocurrent is measured with the help of an ideal ammeter. Two plates of potassium oxide of area $50 c m^{2}$ at separation 0.5 mm are used in the vacuum tube. Photocurrent in the circuit is very small, so we can treat potentiometer circuit an independent circuit. Using the information in the table here, choose correct alternative(s).
Light
1
Violet
2
Blue
3
Green
4
Yellow
5
Orange
6
Red
$\begin{array}{l} λ \\ (in \overset{\circ}{A}) \end{array}$ 4000-4500 4500-5000 5000-5500 5500-6000 6000-6500 6500-7000

Question

Consider the experimental set-up of verification of photoelectric effect shown in the figure. The voltage across the electrodes is measured with the help of an ideal voltmeter and which can be varied by moving jockey J on the potentiometer wire. The battery used in potentiometer circuit is of 20 V and its internal resistance is $2 Ω$ . The resistance of 100 cm along potentiometer wire is $8 Ω$ .

The photocurrent is measured with the help of an ideal ammeter. Two plates of potassium oxide of area $50 c m^{2}$ at separation 0.5 mm are used in the vacuum tube. Photocurrent in the circuit is very small, so we can treat potentiometer circuit an independent circuit. Using the information in the table here, choose correct alternative(s).

Light

1

Violet

2

Blue

3

Green

4

Yellow

5

Orange

6

Red

\begin{array}{l} λ \\ (in \overset{\circ}{A}) \end{array}

4000-4500

4500-5000

5000-5500

5500-6000

6000-6500

6500-7000

Infinity Learn · Accepted Answer

The number of electrons appearing on the surface of the cathode plate, when the jockey is connected at the end P of the potentiometer wire is $n = 8.85 \times 10^{9}$ , even if no radiation falls on the cathode

,

It is found that on incidence of a light (of power $4 \times 10^{- 6} W$ ), current ( $20 μ A$ ) remains almost unchanged even when the jockey is moved from the end P to the middle point of the potentiometer wire. Assuming all the incident photons eject electron, and the light is orange.

,

Red may or may not reject photoelectrons but violet must eject them

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