A person is suffering from myopic defect. He is able to see clear objects placed at 15 cm. What type and of what focal length of lens he should use to see clearly the object placed 60 cm away
|
(a) Concave lens of 20 cm focal length |
(b) Convex lens of 20 cm focal length |
|
(c) Concave lens of 12 cm focal length |
(d) Convex lens of 12 cm focal length |
(a) Concave lens of 20 cm focal length
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In the adjoining circuit diagram each resistance is of 10 W. The current in the arm AD will be
|
(a) |
(b) |
(c) |
(d) |
The variation of induced emf (E) with time (t) in a coil if a short bar magnet is moved along its axis with a constant velocity is best represented as
(a)
|
(b)
|
(c)
|
(d)
|
Two charges each equal to 2μC are 0.5m apart. If both of them exist inside vacuum, then the force between them is
|
(a) 1.89 N |
(b) 2.44 N |
(c) 0.144 N |
(d) 3.144 N |
The magnetic field in a coil of 100 turns and 40 square cm area is increased from 1 Tesla to 6 Tesla in 2 second. The magnetic field is perpendicular to the coil. The e.m.f. generated in it is
|
(a) |
(b) 1.2 V |
(c) 1.0 V |
(d) |
As shown in the figure, a very thin sheet of aluminium is placed in between the plates of the condenser. Then the capacity
|
(a) Will increase |
(b) Will decrease |
|
(c) Remains unchanged |
(d) May increase or decrease |
Field at the centre of a circular coil of radius r, through which a current I flows is
|
(a) Directly proportional to r |
(b) Inversely proportional to I |
|
(c) Directly proportional to I |
(d) Directly proportional to |
A current of 0.1 A circulates around a coil of 100 turns and having a radius equal to 5cm. The magnetic field set up at the centre of the coil is (m0 = 4π × 10–7 weber/amp-metre)
|
(a) 2 × 10–5 Tesla |
(b) 4 × 10–5 Tesla |
(c) 8π × 10–5 Tesla |
(d) 4π × 10–5 Tesla |
