Answer:

Explanation:
Given:
- mass of water,

- initial temperature of water,

- final temperature of water,

- specific heat of water,

<u>Now the amount of heat energy required:</u>



Since all of the mechanical energy is being converted into heat, therefore the same amount of mechanical energy is required.
Answer:
The time rate of change of flux is

Explanation:
Given :
Current
A
Area of plate

Plate separation
m
(A)
First find the capacitance of capacitor,

Where 

F
But 
Where 


Now differentiate above equation wrt. time,



Therefore, the time rate of change of flux is

Answer:
<u><em>A. wavelength</em></u>
Explanation:
The others are about sound and how high it is. That has nothing to do with time.
Answer:

Work done = = 5 kJ
Explanation:
Given data:
volume of nitrogen 



Polytropic exponent n = 1.4
![\frac{T_2}{T_1} = [\frac{P_2}{P_1}]^{\frac{n-1}{n}](https://tex.z-dn.net/?f=%5Cfrac%7BT_2%7D%7BT_1%7D%20%3D%20%5B%5Cfrac%7BP_2%7D%7BP_1%7D%5D%5E%7B%5Cfrac%7Bn-1%7D%7Bn%7D)
putting all value
![\frac{T_2}{473} = [\frac{80}{150}]^{\frac{1.4-1}{1.4}](https://tex.z-dn.net/?f=%5Cfrac%7BT_2%7D%7B473%7D%20%3D%20%5B%5Cfrac%7B80%7D%7B150%7D%5D%5E%7B%5Cfrac%7B1.4-1%7D%7B1.4%7D)

polytropic process is given as



work done 

= 5 kJ
Nothing happens. The frequency is determined at the source,
and it doesn't change along the way.