MHT - CET MCQ

In a study of transistor as an amplifier, the ratio of collector current to emitter current is 0.98. The collector current is 3mA, then base current will be approximately ______.

In a common emitter amplifier circuit using an n-p-n transistor, the phase difference between the input and the output voltages will be: ____________.

Least doped region in a transistor ____________.

The ratio of the velocity of the electron in the first orbit to that in the second orbit is ____________.

Which of the following transition will have highest emission wavelength?

The ratio of slopes m1: ro2 of the lines given in the following graphs is, ____

In series resonant circuit, at resonance, ____________.

The reactance of the coil is 20 `Omega` and its resistance is 20 `Omega`. It is connected to an A.C. source of e.m.f. 220 V. The peak value of the current in the circuit is ____________.

Alternating current cannot be measured by D.C. ammeter because ____________.

A straight conductor of length 2 m moves in a uniform magnetic field of induction 2.5 x `10^-3` T with a velocity. of 4 m/s in a direction perpendicular to its length and also perpendicular to the field. The e.m.f. induced between the ends of the conductor is ______.

In a coil of resistance 150 `Omega`, a current is induced by changing the magnetic flux through it as shown in the figure. The magnitude of change in flux through the coil is ____________.

A solenoid has core of a material with relative permeability 500 and its windings carry a current of 2 A. The number of turns of the solenoid is 500 per metre. The magnetization of the material is ______.

An electron of charge 'e' is revolving in a fixed orbit of radius 'r' with frequency 'f'. Its magnetic dipole moment is ____________.

The magnetic induction at the centre of a coil made from a wire of length 44 m carrying a current of 0.5 A is nearly ____________.

Three long, straight and parallel wires carrying currents are arranged as shown in figure. The force experienced by 10 cm length of wire Q is ____________.

A proton describes a circular path of radius 5 cm in a transverse magnetic field. If the speed of proton is doubled, then the radius of the circular path will be ____________.

A potentiometer wire has a length of 4m and resistance of 5Ω. It is connected in series with 495 Ω resistance and a cell of e.m.f. 4V. The potential gradient along the wire is ______

In Wheatstone's network p = 2 `Omega` , Q = 2 `Omega`, R = 2 `Omega` and S = 3 `Omega`. The resistance with which S is to be shunted in order that the bridge may be balanced is ______.

With resistances P and Q placed in the left and right gaps of a metre bridge, the balance point divides the wire in the ratio of 1/3. When P and Q are increased by 40 n each. the balance point divides the wire in the ratio of 3/5. The values of P and Q will be respectively, ______

The capacity of the conductor does not depend upon ______

Gauss' law helps in ____________.

The equation of a wave of amplitude 0.02 m and period 0.04 s travelling along a stretched string with a velocity of 25 m/s will be ____________.

Three masses 700 g, 500 g, and 400 g are suspended at the end of a spring and are in equilibrium as shown in figure. When the 700 g mass is removed, the system oscillates with a period of 3 seconds; when the 500 g mass is also removed, it will oscillate with a period of ____________.

A particle starting from mean position oscillates simple harmonically with period 4 s. After what time will its kinetic energy be 75% of the total energy?

`( cos 30° = sqrt(3/2))`

A black rectangular surface of area A emits energy E per second at 27°C. If length and breadth is reduced to `(1/3)^("rd")` of initial value and temperature is raised to 327°C then energy emitted per second becomes ______.

If 'f' is the number of degrees of freedom of a molecule of a gas and ratio of molar specific heats of a gas, ϒ = 1 + `2/"f"` where ϒ = Cp/Cv. The ratio of 'ϒ' for monoatomic gas to 'ϒ' for (rigid) f diatomic gas is ______.

A small sphere of mass m is dropped from a great height. After it has fallen 100 m, it has attained its terminal velocity and continues to fall at that speed. The work done by air friction against the sphere during the first 100 m of fall is ______.

The radius of curvature of a plane wavefront ______

The width of depletion layer of a p-n junction diode, when it is (i) forward biased and (ii) reverse biased respectively ______.

Polarised dielectric is equivalent to ______.

At a certain instant, a stationary transverse wave is found to have maximum kinetic energy. The appearance of string at that instant is ____________.

An iron plate has a circular hole of a diameter 11 cm. Find the diameter of the hole when the plate is uniformly heated from 10° C to 90° C.`[alpha = 12 xx 10^-6//°"C"]`

A planet is revolving around the sun in an elliptical orbit as shown in figure. At which point will its K.E. be maximum?

A see-saw of length 6 m is pivoted at its centre. A child of mass 20 kg is sitting at one of its ends. Where should another child, of mass 30 kg, sit on the other end from the centre of see-saw, so that it is balanced?

A body of mass ·m' is moving along a circle of radius 'r' with linear speed 'v'. Now, to change the linear speed to `V/2` and to move it along the circle of radius '4r', required change in the centripetal force of the body is ______.