When an $X$-ray tube operates at a tube voltage of $50 \, kV$,the anode current is $20 \, mA$. If the efficiency of the $X$-ray production is $1 \%$,what is the heat produced per second in calories?

Assertion : Soft and hard $X-$ rays differ in frequency as well as velocity.
Reason : The penetrating power of hard $X-$ rays is more than the penetrating power of soft $X-$ rays.

In an $X-$ray experiment,what do $K_{\alpha}$ and $K_{\beta}$ denote?

$X$-rays of wavelength $0.140 \,nm$ are scattered from a block of carbon. What will be the wavelengths of $X$-rays scattered at $90^{\circ}$ (in $\,nm$)?

$\Delta \lambda$ is the difference between the wavelength of the $K_\alpha$ line and the minimum wavelength of the continuous $X$-ray spectrum when the $X$-ray tube is operated at a voltage $V$. If the operating voltage is changed to $V / 3$,then the above difference is $\Delta \lambda^{\prime}$. Then: