Magnetism And Matter — Physics STD 12 Science — Question

The power factor of L-R circuit is :

Two condensers  and   in a circuit are joined as shown in figure. The potential of point  A is   and that of  B is. The potential of point D will be

(a)

(b)

(c)

(d)

Three charges 4q, Q  and q are in a straight line in the position of 0, l/2 and l  respectively. The resultant force on q will be zero, if Q =

(a) – q

(b) -2q

(c)

(d) 4q

The graph between intensity of light falling on a metallic plate (I) with the current (i) generated is

(a)

(b)

(c)

(d)

The speed of an electron having a wavelength of   is

(a) 7.25 ×

(b) 6.26 ×

(c) 5.25 ×

(d) 4.24 ×

Direction of magnetic field at any point due to a long current carrying conductor is:

An achromatic prism is made by combining two prisms   and ; where μ  represents the refractive index. If the angle of the prism   is 10°,  then the angle of the prism P₂ will be

(a) 5°

(b) 7.8°

(c) 10.6°

(d) 20°

When a charged body is brought near an electroscope:

What is the purpose of filament in electron gun inside a cathode ray tube?

Consider a magnetic dipole kept in the north to south direction. Let P₁, P₂, Q₁, Q₂ be four points at the same distance from the dipole towards north, south, east and west of the dipole respectively. The directions of the magnetic field due to the dipole are the same at:

1. P₁ and P₂
2. Q₁ and Q₂
3. P₁ and Q₁
4. P₂ and Q₂