Choose the correct alternative: 

Intensity of electric field at a point at a perpendicular distance 'r' from an infinite line charge, having linear charge density  is given by, 

• 

• E = 

• E = 

• E = 

If R₁ and R₂ are filament resistance of a 200 W and a 100 W bulb respectively, designed to operate on the same voltage. 

• R₁ = R₂

• R₂ = 2R₁

• R₂ = 4R₁

• R₂ = 4R₁

A metallic wire having length of 2 m and weight of 4 x 10^-3 N is found to remain at rest in a uniform and transverse magnetic field of 2 x 10^-4 T. Current flowing through the wire is: 

• 10 A

• 5 A

• 2 A

• 2 A

When a beam of white light is passed through sodium vapours and then through a spectrometer, spectrum so obtained has two dark lines present in the yellow region. this spectrum is called: 

• band spectrum

• continuous spectrum

• absorption spectrum of sodium

• absorption spectrum of sodium

If I₃ and I₂ represent angular momenta of an orbiting electron in III and II Bohr orbits respectively, then I₃ : I₂ is,

• 3:2

• 9:4

• 2:3

• 2:3

A parallel plate capacitor has a capacitance of 5 . It becomes 50  when a dielectric medium occupies the entire space between its two plates. What is the dielectric constant of the medium? 

Find the EMF of the battery as shown in the figure below: 

Two substances A and B have their relative permeabilities slightly greater and slightly less than 1 respectively.

What do you conclude about A and B as far as their magnetic materials are concerned ?

9.

When does a moved charged particle not experience force while moving through a uniform magnetic field.

What is the turns ratio i.e., transformer ratio, n_s : n_p in an ideal transformer which increases AC voltage from 220 V to 33000 V?