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An electric dipole of length 1cm which is kept with its axis making an angle of 60∘ with a uniform electric field, experiences a torque of 6√3Nm. Calculate the potential energy of the dipole if it has charge ±2nC.

The length of the electric dipole is given as, l = 1cm The angle at which the dipole is placed... View Article

A concave mirror of focal length 10cm is placed at a distance of 35cm from a wall. How far from the wall should an object be placed so that its real image is formed on the wall?

Focal length of the mirror is 10 cm Distance of the object from the wall is 35 cm Now, we... View Article

A uniform but time varying magnetic field is present in a circular region of radius R. The magnetic field is perpendicular and into the plane of the loop and the magnetic field is increasing at a constant rate α.There is a straight conducting rod of length 2R placed as shown in figure. The magnitude of induced emf across the rod is:

Given that, Rate of change of magnetic field,dB/dt=α According to Faraday’s law, emf induced in a closed loop is equal... View Article

With reference to specifying the magnetic field, which of the following physical quantities is not an “element” of the earth’s magnetic field? A) Magnetic dip B) Vertical component of the field C) Magnetic declination D) Horizontal component of the field

answer: (c) vertical component of the field Explanation Earth’s magnetic field is also referred to as the geomagnetic field. The... View Article

A uniform magnetic field B exists in a cylindrical region of radius 10cm as shown in figure. A uniform wire of length 80cm and resistance 4.0Ω is bent into a square frame and is placed with one side along a diameter of the cylindrical region. If the magnetic field increases at a constant rate of 0.010T/s, find the current induced in the frame.

A centripetal force is a net force acting on an item in order to maintain it moving in a circular... View Article

Two identical wires A and B, each of length L, carry the same current I. Wire A is bent into a circle of radius R and wire B is bent to form a square of side ‘a’. If BA and BB are the values of magnetic field at the centre of the circle and square respectively, then what is the value of the ratio BA/BB

Both wires carry current I and are of length L. The magnetic field for a circle of radius R is... View Article

A metal sphere A of radius r1ncharged to a potential ϕ1 is enveloped by a thin walled conducting spherical shell B of radius r2. Then potential ϕ2of the sphere A after it is connected to the shell B by a thin conducting wire will be :-

The charge q1 can be obtained form q1 = uπϵ0ϕ1r1 After the connection, the entire charge q1 will How form... View Article

Cortisone is a molecular substance containing 21 atoms of carbon per molecule. The mass percentage of carbon in cortisone is 69.98%. What is the molecular mass of cortisone?

Let us consider we have 100g of cortisone that means that 100g of cortisone 69.98g is carbon, this is the... View Article

In the arrangement shown, the pulleys and the strings are ideal. The acceleration of block B is

Let us consider that block A is moving up and block B is moving down For block A, From newton’s... View Article

A man slides down a light rope whose breaking strength is η times the weight of man (η<1) . The maximum acceleration of the man so that the rope just breaks is:

To find the equation between tension in the rope, weight of the man, and force due to acceleration of the... View Article

In the cyanide extraction process of silver from argentite ore, the oxidizing and reducing agents used are:

Silver is going to be extracted from argentite ore by using the cyanide process. Other than cyanide, oxidising and reducing... View Article

How do you calculate the number of sigma pi bonds in CH3−CH=CH−C≡CH ?

The given compound is pent-3 -en-1 -yne. The chemical formula of the compound is C5H6 and molecular weight is 66g... View Article

Among the following series of transition of metal ions, the one where all metal ions have 3d2 electronic configuration is: A. Ti+,V4+,Cr6+,Mn7+ B. Ti4+,V3+,Cr2+,Mn3+ C. Ti2+,V3+,Cr4+,Mn5+ D. Ti3+,V2+,Cr3+,Mn4+

Answer: (c) C. Ti2+,V3+,Cr4+,Mn5+ Explanation The charge on the specified metal atoms must be checked and matched with the electrical... View Article

The spring extends by x on loading, then energy stored by the spring is (if T is the tension in spring and k spring constant).

When a weight of W is put to one end of the spring, we may infer that the real length... View Article

When a horse pulls a cart, the force that helps the horse to move forward is the force exerted by, A. the cart on the horse B. the ground on the horse C. the ground on the cart D. the horse on the ground

Answer: B. the ground on the horse Explanation The horse’s forward motion is in the forward direction. Reaction forces are... View Article

An object is placed at a distance of 1.5 m from a screen and a convex lens is interposed between them. The magnification produced is 4. The focal length of the lens is then

The distance between the convex lens or a concave mirror and the focal point of a lens or mirror is... View Article

A force acts on a 2 Kg object so that its position is given as a function of times as x=3t²+5. What is the work done by this force in the first 5 seconds?

Given parameters are The mass of an object = 2Kg The function of time: x=3t2+5 Force: A force is a... View Article

A ball is dropped from height h on a horizontal floor. If it loses 60% of its energy on hitting the floor then upto which it will rise after first rebounce is?

60 percent of the energy is lost. Then use energy conservation as follows: mgh=mgh1+(60/100)mgh Here, m is the mass of... View Article

Two concentric coplanar circular loops made of wire, with resistance per unit length 10⁻⁴Ωm⁻¹ have diameters 0.2 m and 2 m. A time varying potential difference (4+2.5t) is applied to the larger loop. Calculate the current in the smaller loop.

The magnetic field at the centre O due to the current in the larger loop is B=μ0I/2R If r is... View Article

What is the force of attraction between the plates of a parallel plate capacitor?

Electric field by any one plate is given by, E = σ2/ϵ0 …(1) Where, E is the electric field σ... View Article

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