Answer:
9 cm
-36 cm
Explanation:
u = Object distance
v = Image distance
f = Focal length = 12
m = Magnification = 4

Lens equation

Object distance is 9 cm

Image distance is -36 cm (other side of object)
Answer:
A lens placed in a transparent liquid becomes invisible because when refractive index of the material of the lens is equal to the refractive index of the liquid in which lens is placed under this condition no bending of light takes place when it travels from liquid to the lens, so both will start behaving like both are same things.
Explanation:
hope it helps :))
The work done by the machine is equal to the product between the force applied and the distance over which the force is applieds, so in this case:

And the power of the machine is equal to the ratio between the work done by the machine and the time taken:
Answer:
b the answer is b
Explanation:
b is the awnser because it cools after the heat on the water witch lets the steam out
Series circuits split the voltage of resistors, so if you see several diodes connected <em>in series </em>or all next to each other, just a complete loop, it will be in series.
Parallel circuits split the current of resistors, so if you see several diodes connected along different branches or pathways, it will be in parallel.