Answer:
Length of the Pendulum is 14.4 cm
Explanation:
Time period of simple pendulum is given by

time taken for one oscillation is

Pendulum length on the earth surface is

Length of the Pendulum is 14.4 cm
The answer is D because instantaneous means at a particular point in time
Answer: 
Explanation:
Given
Cross-sectional area of wire 
Extension of wire 
Extension in a wire is given by

where, 

for same force, length and material

Divide (i) and (ii)

Answer:
Electron groups could be considered as Lone pair electrons and bonded pairs of electrons.
Answer: Option D & B
Explanation:
The two or more electrons can be bonded by single bond, double bond, covalent bond of electrons can simply be lone pair of electrons. Unshared pair of electrons are generally termed as lone pair of electrons in an atom which are generally present in the outermost shell of atoms. Hence electron groups can be determined by bonded pairs and lone pairs of electrons.
I got this from another brainly user
Answer:
Action and reaction are equal but act in opposite directions