NTA JEE Main 16 th April 2018 Online

A coil of cross-sectional area A having n turns is placed in a uniform magnetic field B. When it is rotated with an angular velocity $$\omega$$, the maximum e.m.f. induced in the coil will be:

A power transmission line feeds input power at 2300 V to a step-down transformer with its primary windings having 4000 turns giving the output power at 230 V. If the current in the primary coil of the transformer is 5 A and its efficiency is 90%, the output current would be:

A plane electromagnetic wave of wavelength $$\lambda$$ has an intensity I. It is propagating along the positive Y-direction. The allowed expressions for the electric and magnetic fields are given by:

A ray of light is incident at an angle of 60$$^\circ$$ on one face of a prism of angle 30$$^\circ$$. The emergent ray of light makes an angle of 30$$^\circ$$ with incident ray. The angle made by the emergent ray with second face of prism will be:

Unpolarized light of intensity I is incident on a system of two polarizers, A followed by B. The intensity of emergent light is $$\frac{I}{2}$$. If a third polarizer C is placed between A and B, the intensity of emergent light is reduced to $$\frac{I}{3}$$. The angle between the polarizers A and C is $$\theta$$, then:

The de-Broglie wavelength ($$\lambda_B$$) associated with the electron orbiting in the second excited state of hydrogen atom is related to that in the ground state ($$\lambda_G$$) by:

Both the nucleus and the atom of some element are in their respective first excited states. They get de-excited by emitting photons of wavelengths $$\lambda_N$$, $$\lambda_A$$ respectively. The ratio $$\frac{\lambda_N}{\lambda_A}$$ is closest to:

At some instant, a radioactive sample S$$_1$$ having an activity 5$$\mu$$Ci has twice the number of nuclei as another sample S$$_2$$ which has an activity of 10$$\mu$$Ci. The half lives of S$$_1$$ and S$$_2$$ are:

In the given circuit the current through zener diode is:

A carrier wave of peak voltage 14 V is used for transmitting a message signal. The peak voltage of the modulating signal given to achieve a modulation index of 80% will be: