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What is the terminal potential difference of a cell when short-circuited?

Answer: The terminal potential difference of a cell when its short-circuited is zero.... View Article

A long straight metal rod has a very long hole of radius ′a′ drilled parallel to the rod axis as shown in the figure. If the rod carries a current ′I′. Find the magnetic induction on the axis of the hole, where OC=c:

a) μ0Ic/π(b2 - a2) b) μ0Ic/π(b2 - a2) c) μ0I(b2 - a2)/2πc d) μ0Ic/2πb2 Answer: b) μ0Ic/π(b2 - a2) Solution: Current density, J = I/A =... View Article

In the circuit element given here, if the potential at B, V_B =0, then the potentials A and D are given as

a) VA = - 1.5 V, VD = + 2 V b) VA = - 1.5 V, VD = + 0.5 V c) VA = + 1.5 V, VD = + 0.5 V d) VA = + 1.5 V, VD = - 0.5 V Answer: d) VA = + 1.5... View Article

A parallel beam of light of wavelength 4000 Å passes through a slit of width 5 x 10^-3 m. The angular spread of the central maxima in the diffraction pattern is

a) 1.6 x 10-3 rad b) 1.6 x 10-4 rad c) 3.2 x 10-3 rad d) 3.2 x 10-4 rad Answer: b) 1.6 x 10-4 rad Solution: Given, Wavelength... View Article

Two coils A and B having turns 300 and 600 respectively are placed near each other, on passing a current of 3.0 ampere in A, the flux linked with A is 1.2 x 10⁻⁴ weber and with B it is 9.0 x 10⁻⁵ weber. The mutual induction of the system is:

a) 2 x 10-5 H b) 3 x 10-5 H c) 4 x 10-5 H d) 6 x 10-5 H Answer: b) 3 x 10-5 H Solution: i1 = 3.0 ampere φ1 = 1.2 x 10-4 weber... View Article

A trolley is being pulled up an incline plane by a man sitting on it (as shown in figure). He applies a force of 250 N. If the combined mass of the man and trolley is 100 kg, the acceleration of the trolley will be [sin 15⁰= 0.26]

a) 2.4 m/s2 b) 9.4 m/s2 c) 6.9 m/s2 d) 4.9 m/s2 Answer: d) 4.9 m/s2 Solution: Fnet = 3T = 3 x 250 = 750 N ω = mgsinθ = 100 x 9.8 x sin... View Article

A layer of glycerine of thickness 1mm is enclosed between a big plate and another plane of area 10⁻²m². If coefficient of viscosity of glycerine is 1kg/(m−s), then the force in newton required to move plate with a velocity of 0.07m/s

a) 7 b) 0.7 c) 70 d) 0.07 Answer: b) 0.7 N Solution: Given that, layer thickness dy=1mm=10−3m Area A=10−2m2 Coefficient... View Article

A square coil of side 25cm having 1000 turns is rotated with a uniform speed in a magnetic field about an axis perpendicular to the direction of the field. At an instant t , the emf induced in the coil is e=200 sin 100 πt . The magnetic induction is

a) 0.50 T b) 0.02 T c) 10-3 T d) 0.1 T e) 0.01 T Answer: e) 0.01 T Solution: Given, e=200 sin 100 πt Comparing the above... View Article

A certain piece of copper is to be shaped into a conductor of minimum resistance. Its length and diameter should be respectively

a) l,d b) 2l,d c) (1/2), 2d d) 2l, d/2 Answer: c) (1/2), 2d Solution: Resistance , R = ρ (L/A) = ρ (L/π(d/2)2) =... View Article

Equipotential surfaces

Equipotential surfaces a) will always be equally spaced b) are closer in regions of large electric fields compared to regions of lower electric... View Article

What is the value of linear velocity, if vector r = 3i-4j+k and ω =5i-6j+6k?

(a) 4i - 13j+ 6k (b) -18i-13j+2k (c) 6i+2J-3k (d) 6i-2j+8k Answer: (b) -18i-13j+2k Solution: v = ω x r = (3i-4j+k) x... View Article

A shower of protons from outer space deposits equal charges +q on the earth and the moon when electrostatic repulsion exactly counterbalances the gravitational attraction. How large is q?

a) b) c) d) Answer: b) Solution: Gravitational Attraction F= GMm/r2 M = Mass of Earth m = Mass of Moon r = Distance between... View Article

A car, starting from rest, has a constant acceleration a1 for a time interval t1 during which it covers a distance s1 . In the next time interval t2, the car has a constant retardation a2 and comes to rest after covering a distance s2 in time t2. Which of the following is correct?

a) b) c) d) Solution: d)... View Article

If the end correction of an open pipe is 0.8 cm then the inner radius of that pipe will be

Solution: Total end correction of open pipe Open pipe has end correction on both sides. End correction on each side x = Diameter of inner... View Article

A horizontal wax bar B rests between a wedge and a vertical wall as shown in the figure. The wedge starts moving towards the wall with a constant acceleration 0.5mm/s^2. The moment the wedge starts moving, a continuous supply of heat from the wall starts melting 1.0mm length of the wax bar per second. If the bar always remains horizontal, which of the following conclusions can you make?

a)The bar first moves downwards and then upwards. b) The bar stops for a moment after 2.0 s from the beginning c) Modulus of displacement of the... View Article

The earth’s magnetic field at the equator is approximately 0.4G. What is the earth’s dipole moment?. (R_{e}=6.4*10^{6}m)

Solution: The equatorial magnetic field is given by the formula: Radius of earth r=... View Article

A positive charge is passing through an electromagnetic field in which vec{E} and vec{B} are directed towards the y−axis & z−axis respectively. If a charge particle passes through the region undeviated, then its velocity is/are represented by (here a, b & c are constant).

a) b) c) d) Solution: b)... View Article

The position of an object moving along the x-axis is given by x = a + bt^2, where a = 8.5 m and b = 2.5 m s^−2 and t is measured in seconds. The average velocity of the object between t = 2s and t = 4s is

Solution: Position is given as x=a+bt^{2} x=a+bt^{2} = 8.5+2.5t^{2} —-----------(1) Substituting t=2s in equation (1) =18.5 m Substituting... View Article

The electric field in a region of space is given by E=5hat{i}+2hat{j} N/C. The flux of E due to this field through an area 1m^2 lying in the y-z plane, in SI units is?

a) 2 b) 4 c) 5 d) 10 Solution:c) 5... View Article

A proton moves along a horizontal line towards the observer. What will be the pattern of concentric circular field lines of magnetic field which produced due to its motion.

Solution: The direction of concentric circular field lines of magnetic field will be in anti-clockwise direction and along the path of the observer.... View Article

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