Answer:
The time rate of change of flux is
Explanation:
Given :
Current A
Area of plate
Plate separation m
(A)
First find the capacitance of capacitor,
Where
F
But
Where
Now differentiate above equation wrt. time,
Therefore, the time rate of change of flux is
Answer:
Object should be placed at a distance, u = 7.8 cm
Given:
focal length of convex lens, F = 16.5 cm
magnification, m = 1.90
Solution:
Magnification of lens, m = -
where
u = object distance
v = image distance
Now,
1.90 =
v = - 1.90u
To calculate the object distance, u by lens maker formula given by:
u = 7.8 cm
Object should be placed at a distance of 7.8 cm on the axis of the lens to get virtual and enlarged image.