In a reversible isothermal process,the change in internal energy is ...... .

If a wire of length $L$ forms a loop of radius $R$ and has $n$ turns,find the magnetic field at the centre of the loop if the current flowing in the loop is $I$.

Initially a photon of wavelength $\lambda_1$ falls on a photocathode and emits an electron of maximum energy $E_1$. If the wavelength of the incident photon is changed to $\lambda_2$,the maximum energy of the electron emitted becomes $E_2$. Then the value of $hc$ ($h=$ Planck's constant,$c=$ velocity of light) is

Which of the following reactions is possible at the anode?

Cathode rays have

In which of the following reactions does $H_2O_2$ act as a reducing agent?