Physics

A parallel plate capacitor has a uniform electric field ' E ' in the space between the plates.
If the distance between the plates is ' d ' and the area of each plate is ' A ', the energy stored in the capacitor is: (ε₀ = permittivity of free space)

An inductor of inductance L, a capacitor of capacitance C and a resistor of resistance ' R '
are connected in series to an ac source of potential difference ' V volts as shown in figure.
Potential difference across L, C and R is 40 V, 10 V and 40 V, respectively. The amplitude of current flowing through LCR series circuit is 10√2 A. The impedance of the circuit is:

A horizontal bridge is built across a river. A student standing on the bridge throws a small ball vertically upwards with a velocity $4{\mathrm{m}\mathrm{s}}^{-1}$ . The ball strikes the water surface after $4\mathrm{s}$ . The height of bridge above water surface is (Take $\mathrm{g}=$ $10{\mathrm{m}\mathrm{s}}^{-2}$  ):

Given below are two statements:

Statement I: Photovoltaic devices can convert optical radiation into electricity.

Statement II: Zener diode is designed to operate under reverse bias in breakdown region.

In the light of the above statements, choose the most appropriate answer from the options given below:

A screw gauge gives the following readings when used to measure the diameter of a wire
Main scale reading: 0 mm
Circular scale reading: 52 divisions
Given that 1 mm on main scale corresponds to 100 divisions on the circular scale. The diameter of the wire from the above data is:

A full wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, capacitor and a load resistance. Which of these components remove the ac ripple from the rectified output

The half life of a radioactive substance is 20 minutes. In how much time, the activity of substance drops to $(1/16{)}^{\text{th}}$  of its initial value?

Consider the following statements (A) and (B) and identify the correct answer.
(A) A zener diode is connected in reverse bias, when used as a voltage regulator.
(B) The potential barrier of p-n junction lies between 0.1 V to 0.3 V.

In hydrogen spectrum, the shortest wavelength in the Balmer series is $\lambda$ . The shortest wavelength in the Bracket series is :

The work functions of Caesium (Cs), Potassium (K) and Sodium (Na) are $2.14\mathrm{e}\mathrm{V},2.30\mathrm{e}\mathrm{V}$ and $2.75\mathrm{e}\mathrm{V}$ respectively. If incident electromagnetic radiation has an incident energy of $2.20\mathrm{e}\mathrm{V}$ , which of these photosensitive surfaces may emit photoelectrons?