Answer:

Explanation:
Given,
Magnetic field,B = 0.5 x 10⁻⁴ T
distance,r= 15 cm = 0.15 m
Current = ?
Using Ampere's law of magnetic field




Current in the wire is equal to 
Answer:
291 K is the answer
Explanation:
to get Kelvin from Celsius use the following
Kelvin = Celsius +273
= 18 +273
= 291
Answer:
(d) Water has a high specific heat.
Explanation:
At night, when the temperature of earth goes down due to loss of heat , the temperature of water is lost slowly and temperature of land is lost fast because of high specific heat of water . Water loses as well as gains temperature comparatively slowly due to its high specific heat .
During daytime when earth gains heat , the temperature of land rises more rapidly than water so water appears cool even during daytime when land becomes hotter . It is also due to high heat holding capacity of water or due to high specific heat of water .