Answer:
the answer here would be A
Force is indirectly proportional to the distance. Therefore when the distance increases the force of attraction increases and the answer would be B
Pic of Bohr Model attached
Answer:19.5 J
Explanation:
Given
mass of block=3 kg
angular frequency=20 rad/sec
spring constant 
we know total energy remain conserved


Where
=kinetic energy
=potential Energy





When mass reaches amplitude its velocity becomes zero
there is only potential energy which is equal to Total energy

Answer:
26
Explanation:
Total power of the circuit
P = V × I = 120 × 20 = 2400 W
Power of each bulb = 90 W
Number of bulbs which work without tripping
N = power of circuit / power of each bulb
N = 2400 / 90
N = 26.66
Number of bulbs should be integer so the number of bulbs be 26.