Answer:
Accuracy measures how close results are to the true or known value. Precision, on the other hand, measures how close results are to one another.
Answer:
Second Trial satisfy principle of conservation of momentum
Explanation:
Given mass of ball A and ball B 
Let mass of ball
and
Final velocity of ball 
Final velocity of ball 
initial velocity of ball 
Initial velocity of ball 
Momentum after collision 
Momentum before collision 
Conservation of momentum in a closed system states that, moment before collision should be equal to moment after collision.
Now, 
Plugging each trial in this equation we get,
First Trial

momentum before collision
moment after collision
Second Trial

moment before collision
moment after collision
Third Trial

momentum before collision
moment after collision
Fourth Trial

momentum before collision
moment after collision
We can see only Trial- 2 shows the conservation of momentum in a closed system.
Answer:
\Delta E=1.22\times 10^{-22}J
Explanation:
The energy of electron in any state is given by
here h is planck's constant n is state of electron L is the infinte potential well m is the mass of electron
We know that 
Potential well dimension = 
Mass of electron 
So energy required to electron to jump from ground state to 3rd state



I would say B. hope it helps
1 Purpose/Question. Ask a question. 2 Research. Conduct background research. ... 3 Hypothesis. Propose a hypothesis. ... 4 Experiment. Design and perform an experiment to test your hypothesis. ... 5 Data/Analysis. Record observations and analyze the meaning of the data. ... 6 Conclusion. Conclude whether to accept or reject your hypothesis.
Sure hope this helps you. Pls mark me as brainiest