NTA JEE Main 9th April 2017 Online

A uniform magnetic field $$B$$ of 0.3 T is along the positive Z-direction. A rectangular loop (abcd) of sides 10 cm $$\times$$ 5 cm carries a current $$I$$ of 12 A. Out of the following different orientations which one corresponds to stable equilibrium?

A sinusoidal voltage of peak value 283 V and angular frequency 320 s$$^{-1}$$ is applied to a series LCR circuit. Given that $$R = 5 \; \Omega$$, $$L = 25$$ mH and $$C = 1000 \; \mu$$F. The total impedance and phase difference between the voltage across the source and the current will respectively be-

The electric field component of a monochromatic radiation is given by $$\vec{E} = 2E_0 \cos kz \cos \omega t \; \hat{i}$$. Its magnetic field $$\vec{B}$$ is then given by:

In an experiment a convex lens of focal length 15 cm is placed coaxially on an optical bench in front of a convex mirror at a distance of 5 cm from it. It is found that an object and its image coincide, if the object is placed at a distance of 20 cm from the lens. The focal length of the convex mirror is-

A single slit of width 0.1 mm is illuminated by a parallel beam of light of wavelength 6000 Å and diffraction bands are observed on a screen 0.5 m from the slit. The distance of the third dark band from the central bright band is:

A laser light of wavelength 660 nm is used to weld Retina detachment. If a laser pulse of width 60 ms and power 0.5 kW is used, the approximate number of photons in the pulse are (Take Planck's Constant, $$h = 6.62 \times 10^{-34}$$ J s)

The acceleration of an electron in the first orbit of the hydrogen atom ($$n = 1$$) is:

Imagine that a reactor converts all the given mass into energy and that it operates at a power level of $$10^9$$ Watt. The mass of the fuel consumed per hour, in the reactor, will be: (velocity of light, $$c$$ is $$3 \times 10^8$$ m s$$^{-1}$$)

The current gain of a common emitter amplifier is 69. If the emitter current is 7.0 mA, collector current is:

A signal is to be transmitted through a wave of wavelength $$\lambda$$, using a linear antenna. The length $$l$$ of the antenna and effective power radiated $$P_{\text{eff}}$$ will be given, respectively, as- ($$K$$ is a constant of proportionality)