Answer:

Explanation:
h = Planck's constant = 
m = Mass of electron = 
k = Coulomb constant = 
e = Charge of electron = 
n = 1 (ground state)
Angular momentum is given by

From Bohr's atomic model we have


The centripetal force will balance the electrostatic force

The diameter is 
Given:
m = 555 g, the mass of water in the calorimeter
ΔT = 39.5 - 20.5 = 19 °C, temperature change
c = 4.18 J/(°C-g), specific heat of water
Assume that all generated heat goes into heating the water.
Then the energy released is
Q = mcΔT
= (555 g)*(4.18 J/(°C-g)*(19 °C)
= 44,078.1 J
= 44,100 J (approximately)
Answer: 44,100 J
Answer:
Option B
Explanation:
Looking at the 3 galvanometer readings given above, for galvanometer A, the reading is -2 mA.
For galvanometer B, the reading is 4 mA.
While for galvanometer C, the reading is -5 MA
Thus, option B is correct.
I would think that you would have to do 42/2=21Hz, but I'm not sure...