Electric Charges and Fields — Physics STD 12 Science — Question

The current in a LR circuit builds up to  th of its steady state value in 4s. The time constant of this circuit is

(a)

(b)

(c)

(d)

We use flint glass prism to disperse polychromatic light because light of different colours

(a) Travel with same speed

(b) Travel with same speed but deviate differently due to the shape of the prism

(c) Have different anisotropic properties while travelling through the prism

(d) Travel with different speeds

A parallel-plate capacitor is connected to a battery. A metal sheet of negligible thickness is placed between the plates. The sheet remains parallel to the plates of the capacitor:

The length of a wire required to manufacture a solenoid of length l and self-induction L is (cross-sectional area is negligible)

Two electric charges 12μC and -6 μC  are placed 20 cm apart in air. There will be a point P on the line joining these charges and outside the region between them, at which the electric potential is zero. The distance of P from -6 μC  charge is

(a) 0.10 m

(b) 0.15 m

(c) 0.20 m

(d) 0.25 m

Two metal spheres of capacitances C₁ and C₂ carry some charges. They are put in contact and then separated. The final charges Q₁ and Q₂ on them will satisfy:

Which of the following particles will experience maximum magnetic force circle when projected with the same velocity perpendicular to a magnetic field?

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

Lux is equal to

(a) 1 lumen/m2

(b) 1 lumen/cm2

(c) 1 candela/m2

(d) 1 candela/cm2

Core of elctromagnets are made of ferromagnetic materials which have: