Answer:
The mass of the block is 1250g.
Explanation:
Given that the formula for density is ρ = mass/volume. Then you have to substitute the values into the formula :

Let density = 250,
Let volume = 5,



Answer:
The rate of transfer of heat is 0.119 W
Solution:
As per the question:
Diameter of the fin, D = 0.5 cm = 0.005 m
Length of the fin, l =30 cm = 0.3 m
Base temperature, 
Air temperature, 
k = 388 W/mK
h = 
Now,
Perimeter of the fin, p = 
Cross-sectional area of the fin, A = 
A = 
To calculate the heat transfer rate:

where

Now,

Explanation:
Right hand thumb rule : Point the thumb of your right hand in the direction of the current flow, the direction of curvature of the fingers will give us the direction of the magnetic field produced by current carrying wire. This rule was given by Maxwell.
1) If the current is moving in upward direction , the direction of the magnetic field will be in anti clock wise direction.
2) If the current is moving in downward direction , the direction of the magnetic field will be in clock wise direction.