# Physics MCQs Part 19

**181. The reciprocal of the square root of the product of the magnetic permeability of a**

**medium and its dielectric constant is?**

**A. The velocity of light**

B. Its reluctance

C. Its impedance

D. Its specific heat

**182. The radius of the circular path of a charge particle moving at right angles to a uniform**

**magnetic field is directly proportional to the?**

A. Flux density

**B. Momentum of the particle**

C. Wave length of ht radiation

D. Charge on the particle

**183. A person cannot see distinctly objects situated at a distance greater than 60 cm from the**

**eye. The power (in diopters) of the lens he must use for the spectacles to correct the defect is?**

A. 1.67 D

B. -1.67 D

C. -50 D

**D. +60 D**

**184. When we decrease the diameter of the objective lens of a telescope, then the resolution**

**of telescope?**

A. Decreases

B. Remains the same

C. Depends on the focal length of the lens

**D. Increases**

**185. A astrono0mical telescope has a magnifying power of 8 when focuses for parallel for**

**parallel rays. If the length of the telescope be 18 cm, the focal length of the objective is?**

A. 16 cm

**B. 10 cm**

C. 144 cm

D. 2.25 cm

**186. The vibrations of an unpasteurized light are taking place?**

**A. In all planes**

B. In one plane

C. In no plane

D. All are true

**187. The quantity of the charge that passes through a conductor while a current of 5.0. A**

**flows through it for 100S (in coulombs) is?**

A. 1800

B. 1000

**C. 500**

D. None of these

**188. Lenz's law in E.M.I follows from Law of Conservation of?**

**A. Energy**

B. Momentum

C. Mass

D. Charge

**189. The longitudinal chromatic aberration for an incident parallel beam of light on a lens of unit focal length is numerically equal to?**

A. Reciprocal of its dispersive power

B. Its dispersive power

**C. Its focal length**

D. None of these

**190. A magnet makes 5 oscillations per minute in earth's magnetic field (H = 0.3 Gauss). By**

**what amount the field should be increased so that the magnet may make 10 oscillations per minute?**

A. 0.3 Gauss

B. 0.6 Gauss

**C. 0.9 Gauss**

D. 1.2 Gauss