Explanation:
Given that,
Object-to-image distance d= 71 cm
Image distance = 26 cm
We need to calculate the object distance


We need to calculate the focal length
Using formula of lens

put the value into the formula



The focal length of the lens is 35.52.
(B). Given that,
Object distance = 95 cm
Focal length = 29 cm
We need to calculate the distance of the image
Using formula of lens

Put the value in to the formula




We need to calculate the magnification
Using formula of magnification



The magnification is 0.233.
The image is virtual.
Hence, This is the required solution.
C. meter per second
Velocity and speed share the same SI unit.
The answer is 9.8 ms^-2, because there is only one force acting on the object so the acceleration will be numerically equal to the gravitational field strength.
Im sure the answer is thallium