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An AC voltage is applied to a resistance R and an inductor L in series. If R and the inductive reactance are both equal to 3 Ω, then the phase difference between the applied voltage and the current in the circuit will be:
A common emitter amplifier has a voltage gain of 50, an input impedance of $100 \text{ } \Omega$ and an output impedance of $200 \text{ } \Omega$. The power gain of the amplifier is:
The circuit is equivalent to:
A ray is incident at an angle of incidence i on one surface of a small angle prism (with angle of prism A) and emerges normally from the opposite surface. If the refractive index of the material of the prism is $\mu$, then the angle of incidence is nearly equal to :
Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stop cock is suddenly opened. The process is :
A circular platform is mounted on a frictionless vertical axle. Its radius $R=2\text{ m}$ and moment of inertia about the axle is $200\text{ kg m}^2$. It is initially at rest. A $50\text{ kg}$ man stands on the edge of the platform and begins to walk along the edge at the speed of $1\text{ ms}^{-1}$ relative to the ground. Time taken by the man to complete one revolution is:
Consider the junction diode as ideal. The value of current flowing through AB is:
A small mass attached to a string rotates on a frictionless table top as shown. If the tension on the string is increased by pulling the string causing the radius of the circular motion to decrease by a factor of $2$, the kinetic energy of the mass will:
An automobile engine develops $100\text{ kW}$ when rotating at a speed of $1800\text{ rev/min}$. What torque does it deliver?
What is the direction of movement of sugars in phloem?
In an alternating current circuit consisting of elements in series, the current increases on increasing the frequency of the supply. Which of the following elements are likely to constitute the circuit? (a) Only resistor (b) Resistor and an inductor (c) Resistor and a capacitor (d) Only a capacitor
The solids which have the negative temperature coefficient of resistance are:
Two bodies of mass $1 \text{ kg}$ and $3 \text{ kg}$ have position vectors $\hat{i}+2\hat{j}+\hat{k}$ and $-3\hat{i}-2\hat{j}+\hat{k}$, respectively. The centre of mass of this system has a position vector:
In which of the following devices, the eddy current effect is not used?
A small-signal voltage $V(t) = V_0 \sin(\omega t)$ is applied across an ideal capacitor C:
A light bulb and an inductor coil are connected to an AC source through a key as shown in the figure below. The key is closed and after some time an iron rod is inserted into the interior of the inductor. The glow of the light bulb:
An LED is constructed from a p-n junction diode using GaAsP. The energy gap is $1.9 \text{ eV}$. The wavelength of the light emitted will be equal to:
The given graph represents the V-I characteristic for a semiconductor device. Which of the following statements is correct?
A body is rolling without slipping on a horizontal surface and its rotational kinetic energy is equal to the translational kinetic energy. The body is:
Water rises to a height $h$ in a capillary tube. If the length of the capillary tube above the surface of water is made less than $h$, then: