Match the column
$(A)$ Hallwachs $\&$ Lenard | $(P)$ Transformers |
$(B)$ Franck-Hertz | $(Q)$ Microwave |
$(C)$ Klystron valve | $(R)$ Quantization of energy levels |
$(D)$ Nicola Tesla | $(S)$ Photoelectric effect |
$A \to S, B \to Q, C \to P, D \to R$
$A \to R, B \to S, C \to P, D \to Q$
$A \to S, B \to R, C \to Q, D \to P$
$A \to Q, B \to P, C \to S, D \to R$
What is called as photon ?
The work function of a metal is
Assertion : The photoelectrons produced by a monochromatic light beam incident on a metal surface, have a spread in their kinetic energies.
Reason : The work function of the metal varies as a function of depth from the surface.
In a photoemissive cell with executing wavelength $\lambda $, the fastest electron has speed $v.$ If the exciting wavelength is changed to $\frac{{3\lambda }}{4}$, the speed of the fastest emitted electron will be
Specific heat of water is $4.2 \,J / g ^{\circ} C$. If light of frequency $3 \times 10^9 \,Hz$ is used to heat $400 \,gm$ of water from $20^{\circ} C$ to $40^{\circ} C$, the number of photons needed will be