Answer:
(a) W=1.20×10⁴J
(b) U= -5.46×10⁴J
(c) Q= -4.26×10⁴J
Explanation:
Given that student does 1.20×10⁴J work
(a) W=1.20×10⁴J
Work done by student,so positive sign
During the process, his internal energy decreases by 5.46×10⁴J.
(b) U= -5.46×10⁴J.
As the Energy decreases therefore negative sign
For (c) Q
We know the formula

Velocity=frequency(wavelength)
24m/s=f(2m)
24/2=f(2)/2
12Hz=f
Q3. (a) 0m/s, as they are asking for initial velocit.
(b)(i) The paper has a large surface area or weighs less than the coin,thus,falls smoothly.
(ii)The coin has more mass than the paper.
(c) They fall at the same acceleration and hit the bottom at the same time.
Their mass doesn't matter in the vacuum.
Answer:
A) The particle will accelerate in the direction of point C.
Explanation:
As we know that
potential at points A, B,C and D as V_A, V_B, V_C, V_D and it is clear from the question that
V_A>V_B>V_C
And we know that flow is always from higher to lower potential (for positive charge due to positive potential energy).
So the charge will accelerate from B toward C.
Hence, the correct option is A.