Question

Why magnetic field lines are radial in moving coil galvanometer?

Answer 1

Explanation:

15. Which of the following salts can produce only two types of radicals?

Options:

(a)

NaKCO3

(b)

CaOCl2

(c)

NH HSO 4 4

(d)

Na NH HPO  4 4 

16. The weight of an empty China dish is 39 g and when a saturated solution of potassium

nitrate is poured into it, its weight is 108 g at

50C

. After evaporating the solution to

dryness, if the weight of the dish along with the crystals is 72 g then the solubility of

potassium nitrate at

50C

is _____.

Options:

(a) 83.9

(b) 95.6

(c) 91.6

(d) 87.4

17. If the roots of the quadratic equation

2

ax bx c    0

are



and



, then the equation

whose roots are

2 

and

2



is

Options:

(a)

 

2 2 2 2 a x b ac x c     2 0

(b)

2 2 2 2 a x b x c    0

(c)

 

2 2 2 2 a x b ac x c     2 0

(d)

 

2 2 2 2 a x b ac x c     2 0

18.

Answer 2

To produce a constant torque on the coil because if we dont apply a radial magnetic field the relation between current and the angle is non linear thus current cant be measured easily and conveniently in terms of deflection in coil because we will get the observation in terms of deflection!

The uniform radial magnetic field keeps the plane of the coil always parallel to the direction of the magnetic field . that is, the angle between the plane of the coil and the magnetic field is zero in all the orientation of the coil.

The radial magnetic field is always parallel to the plane of the coil of the galvanometer, and provides constant torque irrespective of the rotation of the coil. This makes the deflection directly proportional to the current, and facilitates easy calibration of the galvanometer scale.