JEE Advanced2016_S2 - Competishun – Live JEE & NEET Courses and Exam Prep

JEE Advance2016

Paper-2

Question

Light of wavelength $\lambda_{\text {ph }}$ falls on a cathode plate inside a vacuum tube as shown in the figure. The work function of the cathode surface is $\phi$ and the anode is a wire mesh of conducting material kept at a distance d from the cathode. A potential difference V is maintained between the electrode. If the minimum de Broglie wavelength of the electrons passing through the anode is $\lambda_{\mathrm{e}}$, which of the following statement(s) is (are) true?

Select the correct option:

$\lambda_{\mathrm{e}}$ decreases with increase in $\phi$ and $\lambda_{\mathrm{ph}}$

$\lambda_{\mathrm{c}}$ is approximately halved, if d is doubled

For large potential difference $(\mathrm{V} \gg \phi / \mathrm{e}), \lambda_0$ approximately halved if V is made four times

$\lambda_e$ increases at the same rate as $\lambda_{n b}$ for $\lambda_{n b}<\mathrm{hc} / \phi$

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution