Wear an ignition safety switch lanyard so you can turn it off. Most powerboats and PWCs come furnished by the maker with a crisis motor cut-off switch. This wellbeing gadget can stop the motor if the administrator tumbles off the PWC or out of the powerboat, or is generally tossed from the best possible working position.
A > Is the correct answer :)
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:
Number of turns per unit length will be 
Explanation:
We have given that strength of the magnetic field produced by the solenoid B = 7 T
Current in the solenoid i = 200 A
Let the number of turns per unit length is n
Magnetic field due to solenoid is given as
here
is permeability of free space n is number of turns per unit length and i is current
So 
