An em wave is propagating in a medium with a velocity The instantaneous oscillating electric field of this em wave is along +y axis. Then the direction of oscillating magnetic field of the em wave will be along :-
The refractive index of the material of a prism is √2 and the angle of the prism is 30°. One of thetwo refracting surfaces of the prism is made a mirrorinwards , by silver coat ing. A b eam ofmonochromatic light entering the prism from theother face will retrace its path (after reflection fromthe silvered surface) if its angle of incidence on the prism is :-
1 Crore+ students have signed up on EduRev. Have you? Download the App |
The magnetic potential energy stored in a certain inductor is 25 mJ, when the current in the inductor is 60 mA. This inductor is of inductance :-
An object is placed at a distance of 40 cm froma concave mirror of focal length 15 cm. If the objectis displaced through a distance of 20 cm towardsthe mirror, the displacement of the image will be:-
In the combination of the following gates the output Y can be written in terms of inputs A and B as :-
In the circuit shown in the figure, the input voltage Vi is 20 V, VBE = 0 and VCE = 0. The values of IB, IC and β are given by :-
In a p-n junction diode, change in temperature due to heating :-
A small sphere of radius 'r' falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to :-
A sample of 0.1 g of water at 100°C and normalpressure (1.013 x 105 Nm–2) requires 54 cal of heatenergy to convert to steam at 100°C. If the volumeof the steam produced is 167.1 cc, the change ininternal energy of the sample, is :-
Two wires are made of the same material and have the same volume. The first wire has cross-sectional area A and the second wire has cross-sectional area 3A. If the length of the first wire is increased by Δl on applying a force F, how much force is needed to stretch the second wire by the same amount ?
The power radiated by a black body is P and it radiates maximum energy at wavelength 0. If the temperature of the black body is now changed so that it radiates maximum energy at wavelength , the power radiated by it becomes nP. The value of n is :-
A set of 'n' equal resistors, of value 'R' each, areconnected in series to a battery of emf 'E' andinternal resistance 'R'. The current drawn is I. Now,the 'n' resistors are connected in parallel to the samebattery. Then the current drawn from batterybecomes 10 I. The value of 'n' is :-
A battery consists of a variable number 'n' of identical cells (having internal resistance 'r' each) which are connected in series. The terminals of the battery are short-circuited and the current I is measured. Which of the graphs shows the correct relationship between I and n ?
A carbon resistor kΩ is to be marked with rings of different colours for its identification. Thecolour code sequence will be :-
Which one of the following statements is incorrect ?
A moving block having mass m, collides withanother stationary block having mass 4m. Thelighter block comes to rest after collision. When theinitial velocity of the lighter block is v, then the valueof coefficient of restitution (e) will be :-
A body initially at rest and sliding along a frictionless track from a height h (as shown in the figure) just completes a vertical circle of diameter AB = D. The height h is equal to :-
Three objects, A : (a solid sphere), B : (a thin circular disk) and C = (a circular ring), each have the same mass M and radius R. They all spin with the same
angular speed ω about their own symmetry axes. The amounts of work (W) required to bring them to rest, would satisfy the relation :-
A tuning fork is used to produce resonance in aglass tube. The length of the air column in this tubecan be adjusted by a variable piston. At room temperature of 27°C two successive resonances are produced at 20 cm and 73 cm column length. If the frequency of the tuning fork is 320 Hz, the velocity of sound in air at 27°C is :-
An electron falls from rest through a vertical distance h in a uniform and vertically upward directed electric field E. The direction of electrical field is now reversed, keeping its magnitude the same. A proton is allowed to fall from rest in through the same vertical distance h. The time fall of the electron, in comparison to the time fall of the proton is :-
A pendulum is hung from the roof of a sufficiently high building and is moving freely to and fro likea simple harmonic oscillator. The acceleration of the bob of the pendulum is 20 m/s2 at a distanceof 5 m from the mean position. The time period of oscillation is :-
The electrostatic force between the metal plates ofan isolated parallel plate capacitor C having acharge Q and area A, is :-
An electron of mass m with an initial velocity enters an electric field E0 = constant >0) at t = 0. If is its de-Broglie
wavelength initially, then its de-Broglie wavelength at time t is :-
For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is:
When the light of frequency 2v0 (where v0 is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is v1. When the frequency of the incident radiation is increased to 5 v0, the maximum velocity of electrons emitted from the same plate is v2. The ratio of v1 to v2 is :-
The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom,is :-
The moment of the force, at (2, 0, –3), about the point (2, –2, –2), is given by:-
A block of mass m is placed on a smooth inclined wedge ABC of inclination θ as shown in the figure. The wedge is given an acceleration 'a' towards the right. The relation between a and θ for the block to remain stationary on the wedge is :-
A toy car with charge q moves on a frictionless horizontal plane surface under the influence of a uniform electric field . Due to the force , its velocity increases from 0 to 6 m/s in one second duration. At that instant the direction of the field is reversed. The car continues to move for two more seconds under the influence of this field. The average velocity and the average speed of the toy car between 0 to 3 seconds are respectively :-
A student measured the diameter of a small steel ball using a screw gauge of least count 0.001 cm. The main scale reading is 5 mm and zero of circular scale division coincides with 25 divisions above the reference level. If screw gauge has a zero error of – 0.004 cm, the correct diameter of the ball is :-
1 videos|26 docs|121 tests
|
1 videos|26 docs|121 tests
|