Moving Charges and Magnetism — Physics STD 12 Science — Question

In a parabola spectrograph, the velocities of four positive ions P,Q,R and S are v₁, v₂, v₃ and v₄ respectively

(a)	(b)
(c)	(d)

Three equal resistances each of value R are joined as shown in the figure. The equivalent resistance between M and N is

(a) R

(b) 2R

(c)

(d)

If in compound microscope m₁ and m₂ be the linear magnification of the objective lens and eye lens respectively, then magnifying power of the compound microscope will be

(a)

(b)

(c)

(d)

In an electroplating experiment, m gm of silver is deposited when 4 ampere of current flows for 2 minute. The amount (in gm) of silver deposited by 6 ampere of current for 40 second will be

(a) 4 m

(b) m/2

(c) m/4

(d) 2 m

By corpuscular theory of light, the phenomenon which can be explained is ____________.

A spectral line λ = 5000 Å in the light coming from a distant star is observed as a 5200 Å. What will be recession velocity of the star

(a) 1.15

(b) 1.15

(c) 1.15

(d) 1.15 km/sec

For measurement of potential difference, potentiometer is preferred in comparison to voltmeter because

(a) Potentiometer is more sensitive than voltmeter

(b) The resistance of potentiometer is less than voltmeter

(c) Potentiometer is cheaper than voltmeter

(d) Potentiometer does not take current from the circuit

A wire carrying a current i is placed in a uniform magnetic field in the form of the curve y = asin 0 ≤ x ≤ 2L.  The force acting on the wire is

(a)

(b) iBL

(c) 2iBL

(d)  Zero

If one penetrates a uniformly charged spherical cloud, electric field strength:

In the given figure, when key k is closed, then direction of induced current in the coil B IS: