Atoms — Physics STD 12 Science — Question

The field lines of a single positive charge are:

Two Nicols are oriented with their principal planes making an angle of 60°. The percentage of incident unpolarized light which passes through the system is

(a) 50%

(b) 100%

(c) 12.5%

(d) 37.5%

Which impurity is doped in Si to form N-type semi-conductor?

(a) Al

(b) B

(c) As

(d) None of these

A point source of light is used in a photoelectric effect. If the source is removed farther from the emitting metal, the stopping potential:

Light travels through a glass plate of thickness t and having refractive index n. If c is the velocity of light in vacuum, the time taken by the light to travel this thickness of glass is

(a)

(b) tnc

(c)

(d)

In an electric circuit containing a battery, the charge (assumed positive) inside the battery:

1. Always goes from the positive terminal to the negative terminal.
2. May go from the positive terminal to the negative terminal.
3. Always goes from the negative terminal to the positive terminal
4. Does not move.

The magnitude of magnifying power of an astronomical telescope is 5, the focal power of its eyepiece is 10 diopters. The focal power of its objective (in diopters) is:

For a real object, which of the following can produced a real image         

(a) Plane mirror

(b) Concave lens

(c) Convex mirror

(d) Concave mirror

The combination of capacitors with   and   is charged by connecting AB to a battery. Consider the following statements

I.     Energy stored in  = Energy stored in   + Energy stored in  

II.    Charge on C₁ = Charge on C₂ + Charge on C₃

III.  Potential drop across C₁ = Potential drop across C₂ = Potential drop across C₃

Which of these is/are correct

(a) I and II

(b) II only

(c) I and III

(d) III only