271.

A metal rod consumes power P on passing current. If it is cut into two half and joined in parallel, it will consume power

• P

• 2P

• P/4

When a galvanometer is shunted by resistance S, its current capacity increases n times. If the same galvanometer is shunted by another resistance S', its current capacity will increase by n' is given by

• $\frac{(\mathrm{n}+1)\mathrm{S}}{\mathrm{S}\text{'}}$

• $\frac{\mathrm{S} (\mathrm{n}-1)+ \mathrm{S}\text{'}}{\mathrm{S}\text{'}}$

• $\frac{\mathrm{n}+\mathrm{S}}{\mathrm{S}\text{'}}$

• $\frac{\mathrm{S}(\mathrm{n}-1) + \mathrm{S}\text{'}}{\mathrm{S}\text{'}}$

In moving coil galvanometer, the magnetic field used is

• non-uniform

• radial

• uniform

• None of these

A charged particle enters in a strong perpendicular magnetic field. Then its kinetic energy

• increases

• decreases

• remains constant

• None of these

Calculate the current which will produce a deflection of 30° in a tangent galvanometer, if its reduction factor is 3 A.

• 1.732 A

• 0.732 A

• 3.732 A

• 2.732 A

What is shape of· magnet in moving coil galvanometer to make the radial magnetic field?

• Concave

• Horseshoe magnet

• Convex

• None of the above

A cyclotron can accelerate

• β-particles

• α-particles

• high-velocity gamma rays

• high-velocity X-rays

A galvanometer coil has a resistance of 15 Ω and gives full-scale deflection for a current of 4 mA. To convert it to an ammeter of range 0 to 6 A

• 10 mΩ resistance is to be connected in parallel to the galvanometer

• 10 mΩ resistance is to be connected in series with the galvanometer

• 0.1 Ω resistance is to be connected in parallel to the galvanometer

• 0.1 Ω resistance is to be connected in series with the galvanometer

A solenoid 1.5 m long and 0.4 cm in diameter possesses 10 turns/cm length. A current of 5 A falls through it. The magnetic field at the axis inside the solenoid is

• 2π × 10^-3 T

• 2π × 10^-5 T

• 4π × 10^-2 T

• 4π × 10^-3 T

A proton and a deuteron with the same initial kinetic energy enters a magnetic field in a direction perpendicular to the direction of the field. The ratio of the radii of the circular trajectories described by them is

• 1 : 4

• 1 : √2

• 1 : 1

• 1 : 2