Answer:
The energy absorbed by a hydrogen atom is 1.549 X10⁻¹⁹ J
Explanation:
Using Bohr's equation; the energy absorbed by the hydrogen atom can be calculated as follows:

When an electron moves from a lower energy level to a higher energy level, energy is absorbed by the atom.
Lower energy level (n₂) = 3
Higher energy level (n₁) = 5
1 eV = 1.602X10⁻¹⁹ C

ΔE = 1.549 X10⁻¹⁹J
The energy absorbed by a hydrogen atom to transition an electron from n = 3 to n = 5 is 1.549 X10⁻¹⁹ J
Question 9 is 100 N.
Question 10 is No, the bike's motion is not changing so it could be at rest or moving at a constant velocity.
Question 11 is Be doubled.
Question 12 is Ella is correct.
Hope i helped.
Answer: C and D
The equipment would have stayed in the same exact location indefinitely until the very moment the astronaut applied force to it.
The equipment will continue moving in the same direction indefinitely unless another force is applied to stop it.
Explanation: According to Newton's first law of motion which state that; A body at rest will continue to be at rest, or in linear motion will continue to move in a straight line, unless an external force act on it.
The equipment would have stayed in the same exact location indefinitely until the very moment the astronaut applied force to it.
immediately the astronaut apply force to the object by pushing in, Newton's first law will be manifested in which the equipment will continue moving in the same direction indefinitely unless another force is applied to stop it.
Answer: 37.5 kg in 3 s.f.
Explanation: