Class 12th

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?

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?

The minimum wavelength of X-rays produced by an electron accelerated through a potential difference of V volts is proportional to:

For Young's double slit experiment, two statements are given below:

Statement I: If screen is moved away from the plane of slits, angular separation of the fringes remains constant.

Statement II: If the monochromatic source is replaced by another monochromatic source of larger wavelength, the angular separation of fringes decreases.

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

Light travels a distance $x$ in time $t1$ in air and $10x$  in time $t2$ in another denser medium. What is the critical angle for this

In a plane electromagnetic wave travelling in free space, the electric field component oscillates sinusoidally at a frequency of $2.0*{10}^{10}\mathrm{H}\mathrm{z}$ and amplitude $48{\mathrm{V}\mathrm{m}}^{-1}$ . Then the amplitude of oscillating magnetic field is:

(Speed of light in free space $=3*108{\mathrm{m}\mathrm{s}}^{-1}$  )