Answer:
636.619772368 A
Explanation:
= Torque = 
B = Magnetic field of Earth = 
A = Area
d = Diameter = 20 cm
Current is given by

The current is 636.619772368 A
Answer:
It depends on the electro-magnetic frequency of the light and object's nature of atoms.
Answer:
(a) convex mirror
(b) virtual and magnified
(c) 23.3 cm
Explanation:
The having mirror is convex mirror.
distance of object, u = - 20 cm
magnification, m = 1.4
(a) As the image is magnified and virtual , so the mirror is convex in nature.
(b) The image is virtual and magnified.
(c) Let the distance of image is v.
Use the formula of magnification.

Use the mirror equation, let the focal length is f.

Radius of curvature, R = 2 f = 2 x 11.67 = 23.3 cm
<em>The answer is </em>Ninth <em>and </em>Tenth <em>grade so the answer would be</em> B
<em>I hope this helps you </em>