Answer:

Explanation:
As we know that when electron moved in electric field then work done by electric field must be equal to the change in kinetic energy of the electron
So here we have to find the work done by electric field on moving electron
So we have



now the distance moved by the electron is given as

so we have



now we have to convert it into keV units
so we have


The kinetic energy of a book on a shelf is equal to the work done to lift the book to the shelf is false. The kinetic energy on the shelf is zero because it is not in action.
<span>Cobalt-60 is undergoing a radioactivity decay.
The formula of the decay is n=N(1/2)</span>∧(T/t).
<span>Where N </span>⇒ original mass of cobalt
<span> n </span>⇒ remaining mass of cobalt after 3 years
T ⇒ decaying period
t ⇒ half-life of cobalt.
So,
0.675 = 1 × 0.5∧(3/t)
log 0.675 = log 0.5∧(3/t)
3/t = log 0.675 ÷log 0.5
3/t= 0.567
t = 3÷0.567
= 5.290626524
the half-life of Cobalt-60 is 5.29 years.
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Answer:
False.
Explanation:
All atoms of the same element have the same number of protons, but some may have different numbers of neutrons.
Answer:
the final pressure of the gas is 60 kPa.
Explanation:
Given;
initial pressure of the gas, P₁ = 50 kPa = 50,000 Pa
initial temperature of the gas, T₁ = 27⁰ C = 27 + 273 = 300 k
final temperature of the gas, T₂ = 87⁰ C = 87 + 273 = 360 K
Let the final pressure of the gas = P₂
Apply pressure law;

Therefore, the final pressure of the gas is 60 kPa.