Latest Posts

The north pole of a bar magnet is rapidly introduced into a solenoid at one end (say a). which of the following statements correctly depicts the phenomenon taking placea) No induced emf is developed b) The end A of the solenoid behave as south pole c) The end A of the solenoid behave as north pole d) The end A of the solenoid acquires positive potential

Answer:(c) It happens in accordance with the Lenzs law. The end A becomes north pole, to oppose the motion of... View Article

when a copper sphere is heated, maximum percentage change will be observed in (1) radius (2) area (3) volume (4) none of these

Answer: (3) volume Explanation Change in radius =rΔr=X Change in area =Δ(4πr2/(4πr2) =Δr2/r2 = 2Δr/r =2X Change in Volume =Δ(4/3πr3/(4/3πr3)... View Article

The energy required to break one mole of Cl−Cl bonds in the Cl2 is 242 KJ mol−1 . The longest wavelength of light capable of breaking a single Cl−Cl bond is:

The amount of energy necessary to break a chemical bond between A and B AB is known as bond dissociation... View Article

A block of mass 2 kg is placed on the floor (μ = 0.4). a horizontal force of 7 n is applied on the block. the force of friction between the block and floor is

The mass of the block as given in the question is 2kg. The coefficient of static friction is 0.4. Force... View Article

Three charges q, q and q are placed at the vertices of an equilateral triangle of side l as shown in the figure. if the net electrostatic energy of the system is zero, then q is equal to

Electric potential energy is possessed by an object by the virtue of two elements, those being, the charge possessed by... View Article

Consider a uniform square plate of side a and mass m. The moment of inertia of this plate about an axis perpendicular to its plane and passing through one of its corner is:

We can easily find R using the Pythagoras theorem, ⇒R=√ a2−(a/2)2 =a√2 We know that for a square plate, the... View Article

The value of acceleration due to gravity ′g′, at earth’s surface is 10m/s2. Its value at the centre of the earth which is assumed to be sphere of radius ′R′ and uniform mass density, is

There is no mass at exact center of Earth to provide a gravitational pull and thus a gravitational acceleration⇒acceleration due... View Article

A proton, a deuteron and an α-particle are projected perpendicular to the direction of a uniform magnetic field with same kinetic energy. The ratio of the radii of the circular paths described by them is

Radius of circular path r = mv/Bq Using p = mv = √2mK where K is the kinetic energy of... View Article

Friction does not depend on the nature of the surface in contact.

The frictional force works to inhibit relative motion between two surfaces when they are in contact. The body can move... View Article

Let ar and at represent radial and tangential acceleration . the motion of particle may be circular if : ( assume that only momentary rest is allowed) A. ar = at = 0 B. ar = 0 and at≠0 C. ar ≠ 0 and at=0 D.ar≠ 0 and at≠0

Tangential acceleration is the reason of a particle travelling faster or slower in a circular motion. A uniform motion is... View Article

Two circular, similar, coaxial loops carry equal currents in the same direction. If the loops are brought nearer, what will happen?

Answer: Current will decrease in each loop Explanation The flux between the two loops rises as they are brought closer.... View Article

The displacement of a particle is given by x=(t−2)2 where x is in metres and t is in seconds. The distance covered by the particle in first 4 seconds is

The distance travelled is given by x=(t−2)2 = t2–4t+4 As velocity is given by v = dx/dt v=2t−4 Distance covered=∫∣v∣dt... View Article

A body revolves with constant speed v in a circular path of radius r . the magnitude of its average acceleration during motion between two points in diametrically opposite direction is:

The acceleration will change as there is change in the velocity at any direction.Speed of the body is given to... View Article

A charge q is placed at every corner of a square having side a. how much charge must be placed at its centre to bring the system in equilibrium?

Let the side length of the square be a. In △ACD, ⇒AD2 + CD2 = AC2 ⇒ a2 + a2... View Article

The minimum and maximum distances of a satellite from the centre of the Earth are 2R and 4R respectively, where R is the radius of Earth and M is the Earth. The radius of curvature at the point of minimum distance is

Using angular momentum conservation, which implies that any of the individual angular momenta can vary as long as the aggregate... View Article

A charged particle of mass m and charge q is released from rest in an electric field of constant magnitude E. The kinetic energy of the particle after time t is

Newton’s all three laws of motion are very important for the questions in which objects falling from a particular height... View Article

The ratio of escape velocity at earth ve to the escape velocity at a planet vp whose radius and mean density are twice as that of earth is:

Escape velocity is an initial velocity at which, a body when thrown will leave the gravitational field of earth and... View Article

In a current carrying load solenoid, the magnetic field produced does not depend upon

A solenoid is a common term for a wire coil used as an electromagnet. It also applies to any system... View Article

A uniform sphere of mass 500 g rolls without slipping on a plane surface so that its centre moves at a speed of 0.02 m/s . The total kinetic energy of rolling sphere would be (in J)

Consider v to be the velocity of the sphere’s centre. When rolling without sliding, the angular speed of the centre... View Article

A current of 1.40 ampere is passed through 500mL of 0.180M solution of zinc sulphate for 200 seconds. The molarity of Zn2+ ions after deposition of zinc is:

The equation is given by Zn2++ 2e− ⟶ Zn Faraday = Charge/96500 =1.40×200/96500 = 2.90×10−3 mol ∴Zn deposited =2.90×10−3/2 =1.45×10−3... View Article

«
1
…
613
614
615
616
617
…
5,472
»