Physics Test - 4

The resistance of a coil for D.C. is in ohms. In A.C., the resistance

An X - ray tube is operated at a constant potential difference and it is required to get X - ray of wavelength not less then 0. 2 nano-metres. Then the potential difference in kilo-volts is [ h = 6.63 x 10^-34 J − sec ; e = 1.6 x 10^-19 C ; c = 3x 10⁸ m s^-1 ]

A photon of energy 2. 5eV and wavelength λ falls on a metal surface and the ejected electrons have a velocity 'V' . If the wave length λ of incident light is decreased by 20%, the velocity of emitted electrons is doubled, then the work function of the metal is

Current flows in the semi-conductors through

A 2μ F capacitor is charged to 100 volt and then its plates are connected by a conducting wire. The heat produced is

A 4 V battery of internal resistance 1 Ω sends a current through a 3 Ω resistor. The terminal potential difference is

The maximum current that flows through a fuse wire before it blows out varies with its radius r as

Consider telecommunication through optical fibres. Which of the following statements is not correct

Which of the following is a non-ohmic resistor?

When a proton is accelerated with 1 volt potential difference, then its kinetic energy is