- AThe strips of foils opens up.
- BThe strips of foils close.
- CThe strips open and close simultaneously.
- DThe strips neither open nor close.
Explanation:
When a charged body is brought near the top conducting disc of an electroscope, the disc gets induced with charges. These charges run down to the metal strips hanging from the paper clip. Now as both the strips get similar charge, those repel each other and thus open up.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
A coil of 40 W resistance has 100 turns and radius 6 mm is connected to ammeter of resistance of 160 ohms. Coil is placed perpendicular to the magnetic field. When coil is taken out of the field, 32 m C charge flows through it. The intensity of magnetic field will be
|
(a) 6.55 T |
(b) 5.66 T |
(c) 0.655 T |
(d) 0.566 T |
Two identical charged spherical drops each of capacitance C merge to form a single drop. The resultant capacitance is
|
(a) Equal to 2C |
(b) Greater than 2C |
|
(c) Less than 2C but greater than C |
(d) Less than C |
The resistance of a 5 cm long wire is 10 W. It is uniformly stretched so that its length becomes 20 cm. The resistance of the wire is
|
(a) 160 W |
(b) 80 W |
(c) 40 W |
(d) 20 W |
The figure shows some of the electric field lines corresponding to an electric field. The figure suggests
|
(a) |
(b) |
(c) |
(d) |
The plates of a parallel plate capacitor of capacity 50 μC are charged to a potential of 100 volts and then separated from each other so that the distance between them is doubled. How much is the energy spent in doing so
|
(a) 25 |
(b) -12.5 |
(c) -25 |
(d) 12.5 |
A candle placed 25 cm from a lens, forms an image on a screen placed 75 cm on the other end of the lens. The focal length and type of the lens should be
|
(a) + 18.75 cm and convex lens |
(b) – 18.75 cm and concave lens |
|
(c) + 20.25 cm and convex lens |
(d) – 20.25 cm and concave lens |