Which of the following velocity-time graph shows a realistic situation for a body in motion :-
Answer: (b) Explanation In a practical circumstance, the body cannot have more than one velocity at the same time, or,... View Article
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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... 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... 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 Explanation Let’s start with the most basic scenario: On the surface of the Earth, i.e., at a... 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... 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... 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,... 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... 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... View Article
A Zener diode works on: A) zero bias B) reverse bias C) forward bias D) infinite bias
Answer: (b) reverse bias Explanation When a PN junction diode is heavily doped with impurities, the depletion layer’s breadth narrows... 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... 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... 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,... 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... View Article
Which of the following has more inertia? A five-rupee coin or a one-rupee coin.
Inertia is a property of a body that causes it to prefer to be at rest or in motion. Let... View Article
The frequency n of vibration of stretched string depends upon its length l, its mass per unit length m and Tension t in the string Obtain dimensionally an expression for frequency n.
Let the relation be: Frequency v = KLafbmc where k is a dimensionless constant The dimension of each quantity are:... View Article
Two forces, while acting on a particle in opposite; directions, have the resultant of 10N. If they act at right angles to each other, the resultant is found to be 50N. Find the two forces.
The resultant force is described as the total amount of force acting on the object or body along with the... View Article
What will happen to a compass needle when the compass is placed below a wire and a current is made to flow through the wire? Give a reason to justify your answer.
Assume we’re holding a current-carrying straight conductor in our right hand, with the thumb pointing in the current’s direction. The... View Article
An object is thrown vertically upwards to a height of 10 m. Calculate its (a) Velocity with which it was thrown upward. (b) Time taken by the object to reach the highest point.
We have given the maximum vertical height attained by the object is h=10m . (a)To calculate the initial velocity of... View Article
A circular loop of radius 0.0157 m carries a current of 2.0 amp.The magnetic field at the center of the loop is
The magnetic field due to a circular loop is given by: B = μ0/4π 2πi/r =10−7 × 2π×2/ 0.0157 = 8... View Article
