Nuclei — Physics STD 12 Science — Question

The unit of electric field intensity is:

In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of:

Two conducting circular loops F and G are kept in a plane on either side of a straight current-carrying wire as shown in the figure below.
If the current in the wire decreases in magnitude, the induced current in the loops will be:

A two metre wire is moving with a velocity of 1 m/sec perpendicular to a magnetic field of 0.5 weber/m². The e.m.f. induced in it will be

(a) 0.5 volt

(b) 0.1 volt

(c) 1 volt

(d) 2 volt

What is the force exerted by a stationary charge when it is placed in a magnetic field?

The plate current i_p in a triode valve is given   where i_p is in milliampere and V_p and V_g are in volt. If r_p = 10⁴ ohm, and , then for   and , what is the value of K and grid cut off voltage

(a) – 6V, (30)3/2

(b) -6 V,

(c) + 6V, (30)3/2

(d) + 6V, (1/30)3/2

If the wavelength of light is 4000 Å, then the number of waves in 1 mm length will be

(a) 25

(b) 0.25

(c) 0.25

(d) 25

The path executed by a charged particle whose motion is perpendicular to magnetic field i

(a) A straight line

(b) An ellipse

(c) A circle

(d) A helix

The most penetrating radiation out of the following is

(a) X-rays

(b) β -rays

(c) α -  particles

(d) γ - rays

An electron, a proton, a deuteron and an alpha particle, each having the same speed are in a region of constant magnetic field perpendicular to the direction of the velocities of the particles. The radius of the circular orbits of these particles are respectively R_e, R_p, R_d and R_a. It follows that

(a)

(b)

(c)

(d)