Here's a quick way to find out. Pick up your glasses, bifocals work best, and find the focal length with a flashlight against a book. If I remember right, the object should be magnified and upside down. So, A.
Answer:
8 seconds
Explanation:
power (P) is defined as the rate at which work is done.
power is measured in Watts (W) , when the work done is measured in Joules (J) and time in seconds
by the definition of power,
Explanation:
Given that,
Size of object, h = 0.066 m
Object distance from the lens, u = 0.210 m (negative)
Focal length of the converging lens, f = 0.14 m
If v is the image distance from the lens, we can find it using lens formula as follows :
(a) Magnification,
(b) Magnification,
h' is image height
Hence, this is the required solution.