NTA JEE Main 22nd April 2013 Online

An LCR circuit as shown in the figure is connected to a voltage source $$V_{ac}$$ whose frequency can be varied. The frequency, at which the voltage across the resistor is maximum, is :

In a series L - C - R circuit, $$C = 10^{-11}$$ Farad, $$L = 10^{-5}$$ Henry and $$R = 100$$ Ohm, when a constant D.C. voltage E is applied to the circuit, the capacitor acquires a charge $$10^{-9}$$ C. The D.C. source is replaced by a sinusoidal voltage source in which the peak voltage $$E_0$$ is equal to the constant D.C. voltage E. At resonance the peak value of the charge acquired by the capacitor will be :

A plane electromagnetic wave in a non-magnetic dielectric medium is given by $$\vec{E} = \vec{E_0}(4 \times 10^{-7}x - 50t)$$ with distance being in meter and time in seconds. The dielectric constant of the medium is :

The focal length of the objective and the eyepiece of a telescope are 50 cm and 5 cm respectively. If the telescope is focussed for distinct vision on a scale distant 2 m from its objective, then its magnifying power will be :

The image of an illuminated square is obtained on a screen with the help of a converging lens. The distance of the square from the lens is 40 cm. The area of the image is 9 times that of the square. The focal length of the lens is :

This question has Statement-1 and Statement-2. Of the four choices given after the Statements, choose the one that best describes the two Statements.
Statement-1: Short wave transmission is achieved due to the total internal reflection of the e-m wave from an appropriate height in the ionosphere.
Statement-2: Refractive index of a plasma is independent of the frequency of e-m waves.

This question has Statement-1 and Statement-2. Of the four choices given after the Statements, choose the one that best describes the two Statements.
Statement-1: In Young's double slit experiment, the number of fringes observed in the field of view is small with longer wavelength of light and is large with shorter wavelength of light.
Statement-2: In the double slit experiment the fringe width depends directly on the wavelength of light.

Orbits of a particle moving in a circle are such that the perimeter of the orbit equals an integer number of de-Broglie wavelengths of the particle. For a charged particle moving in a plane perpendicular to a magnetic field, the radius of the $$n^{th}$$ orbital will therefore be proportional to :

The half-life of a radioactive element A is the same as the mean-life of another radioactive element B. Initially both substances have the same number of atoms, then :

Figure shows a circuit in which three identical diodes are used. Each diode has forward resistance of 20$$\Omega$$ and infinite backward resistance. Resistors $$R_1 = R_2 = R_3 = 50\Omega$$. Battery voltage is 6 V. The current through $$R_3$$ is :