NTA JEE Main 25th July 2021 Shift 1

In the given figure, there is a circuit of potentiometer of length AB = 10 m. The resistance per unit length is 0.1 $$\Omega$$ per cm. Across AB, a battery of emf E and internal resistance r is connected. The maximum value of emf measured by this potentiometer is:

A linearly polarised electromagnetic wave in vacuum is $$$E = 3.1\cos 1.8z - 5.4 \times 10^6 t \hat{i}$$$ N C$$^{-1}$$ is incident normally on a perfectly reflecting wall at $$z = a$$. Choose the correct option.

A ray of laser of a wavelength 630 nm is incident at an angle of 30$$^\circ$$ at the diamond-air interface. It is going from diamond to air. The refractive index of diamond is 2.42 and that of air is 1. Choose the correct option.

In the Young's double slit experiment, the distance between the slits varies in time as $$dt = d_0 + a_0 \sin\omega t$$; where $$d_0$$, $$\omega$$ and $$a_0$$ are constants. The difference between the largest fringe width and the smallest fringe width obtained over time is given as:

What should be the order of arrangement of de-Broglie wavelength of electron $$\lambda_e$$, an $$\alpha$$-particle $$\lambda_\alpha$$ and proton $$\lambda_p$$ given that all have the same kinetic energy?

A particle of mass 4M at rest disintegrates into two particles of mass M and 3M, respectively, having non zero velocities. The ratio of de-Broglie wavelength of particle of mass M to that of mass 3M will be:

Some nuclei of a radioactive material are undergoing radioactive decay. The time gap between the instances when a quarter of the nuclei have decayed and when half of the nuclei have decayed is given as: (where $$\lambda$$ is the decay constant)

The half-life of $$^{198}$$Au is 3 days. If atomic weight of $$^{198}$$Au is 198 g mol$$^{-1}$$, then the activity of 2 mg of $$^{198}$$Au is [in disintegration second$$^{-1}$$]:

Identify the logic operation carried out.

In amplitude modulation, the message signal $$V_m(t) = 10\sin 2\pi \times 10^5 t$$ volts and carrier signal $$V_C(t) = 20\sin 2\pi \times 10^7 t$$ volts. The modulated signal now contains the message signal with lower side band and upper side band frequency, therefore the bandwidth of modulated signal is $$\alpha$$ kHz. The value of $$\alpha$$ is: