Answer:
1/f = 1/D' + 1/D
The magnification equation relates the ratio of the image distance and object distance to the ratio of the image height (h^i) and object height (h^o). The magnification equation is stated as follows:
M= H^i/H^o = D^i/D^o
Answer:
A. 30.7cm
B. 
C. The electric field is directed away from the point of charge
Explanation:
A.

B.
Considering Gauss's law

C. The electric field directed away from the point of charge when the charge is positive.
Here in this type of question we can use momentum conservation
It is because we can see there is no external force on the system
So we can use momentum conservation principle

here we know that




now after bird sits on it then final speed of the both will be same




so final speed will be 1 m/s