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A block of mass m = 1kg is placed on a smooth surface and is connected with a spring of constant K = 100N/m and another end of spring is connected to a fixed wall as shown. The block is pulled by a distance A = 0.10 m from its natural length and released at t = 0(A) The maximum speed is after t=π/20s (B) Time taken to cover the first 0.10 m, t=π/20s (C) Time taken to cover the first 0.05 m, t=π/40s (D) Time taken to cover the first 0.05 m, t=π/30s

Given parameters are K = 100N/m m = 1 kg L = 1 m Now, using the formula for the angular frequency of a spring in simple harmonic motion, ω... View Article

A plane electromagnetic wave of frequency 25 MHz travels in free space along the x-direction. At a particular point in space and time, E=6.3 j^V/m. What is Bat this point?

The magnitude of the magnetic field will be given by the magnitude of the electric field divided by the speed of light. From the direction of the... View Article

Consider the situation shown in figure. The wall is smooth but the surface of A and B in contact are rough. The friction on B due to A in equilibrium- (a) is upward (b) is downward (c) is zero (d) the system can’t remain in equilibrium

Here it is given that two blocks A and B who are attached together. From the figure we can see the different forces acting on both the blocks.... View Article

The magnetic induction at a point P which is 4cm distant from a long current carrying wire is 10 −3T. The field of induction at a distance 12 cm from the same current would be?

Magnetic induction, also called electromagnetic induction refers to the production of voltage (or EMF) across an electrical conductor placed... View Article

A body is thrown vertically upwards. Which one of the following graphs correctly represents the velocity vs time?

a) b) c) d) Velocity of a body thrown vertically upwards can be given as: vf= vi+ at where a=−g (always acts in downward direction)... View Article

The maximum emission wavelength at temperature 2000K is 4μm. The maximum wavelength corresponding to temperature 2400K will be

Wien’s law or Wien’s displacement law, named after Wilhelm Wien was derived in the year 1893 which states that black body radiation... View Article

Which of the following velocity-time graph shows a realistic situation for a body in motion :-

Answer: (b) In a practical circumstance, the body cannot have more than one velocity at the same time, or, to put it another way,... View Article

The magnetic field in a travelling electromagnetic wave has a peak value of 20 nT. What is the peak value of electric field strength?

The product of the peak value of the magnetic field and the velocity of light is the peak value of electric field strength. Thus, the value of... View Article

Consider the charges q, q and –q placed at the vertices of the equilateral triangle, as shown in the figure. What is the force on each charge?

The electrostatic force is the electric force that exists between two static and charged particles. Depending on whether the particles are... View Article

A body weighs 72 N on the surface of the earth. What is the gravitational force on it due to the Earth at a height equal to half the radius of the earth? (1) 48 n (2) 32 n (3) 30 n (4) 24 n

Answer: (2) 32N Let's start with the most basic scenario: On the surface of the Earth, i.e., at a height R (where R is the radius of the... View Article

Two copper wires, one of length 1 m and the other of length 9 m, are found to have the same resistance. Their diameters are in the ratio :

An electrical conductor's electrical resistance is the resistance to the passage of an electric current through it. The resistance of a wire... View Article

Explain parallax method for measuring distance of a nearly star.

The process of measuring two angles and sides of a triangle created by the star, earth on one side, and the other side six months later is known... View Article

A parallel plate capacitor is charged and then isolated. The effect of increasing the plate separation on charge, potential and capacitance respectively are:

The capacitor is charged and then isolated, according to the question. It indicates that as plate separation increases or decreases, the charge... View Article

If momentum of an object is increased by 10% then its kinetic energy will increase by?

Answer: 21% The relationship between the kinetic energy and momentum of a body is K.E=P2/2m. Given that, if momentum is increased by 10%, then... View Article

The minimum distance between an object and its real image formed by a convex lens is:

Suppose I be the real image of an object at O. Let d represent the distance between them. If the image is x distance from the lens's centre, then... View Article

A Zener diode works on: A) zero bias B) reverse bias C) forward bias D) infinite bias

Answer: (b) reverse bias When a PN junction diode is heavily doped with impurities, the depletion layer's breadth narrows due to the larger... View Article

A particle of mass M at rest decays into two masses m1 and m2with non-zero velocities. What is the ratio λ1/λ2 of de Broglie wavelengths of particles?

We know that, according to de-Broglie’s hypothesis, the momentum of the particle is, p = hc/λ Here, h is Planck’s constant... View Article

The gravitational force between two bodies is ′ F ′ . If the mass of each body is doubled and distance between them is halved then the force between them will be :

The force between two masses is directly proportional to the product of their masses and inversely proportional to the square of the distance... View Article

Assertion In a simple battery circuit, the point of the lowest potential is positive terminal of the battery. Reason The current flows towards the point of the higher potential, as it does in such a circuit from the negative to the positive terminal. In a simple battery circuit, the point of the lowest potential is positive terminal of the battery.

Answer: A battery's positive terminal is the place of highest potential, and current flows from there to the negative terminal, or from +ve to... View Article

How many images of an object are formed if two adjacent walls and the ceiling of a rectangular room are mirror surfaced?

The incident ray will be reflected at an angle in a plane mirror. The incidence angle and the reflection angle will be the same. When two mirrors... View Article

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