Answer:
The minimum magnetic field is 0.078 T.
Explanation:
Given that,
Current = 16 A
Side = 15 cm
Mass 
Mass each segment in given square loop is

We need to calculate the torque due to gravity
Using formula of torque


The torque due to magnetic field


The equilibrium condition

Put the value into the formula



Put the value into the formula


Hence, The minimum magnetic field is 0.078 T.
Pearl Ash is an example of an Impure Potassium Carbonate
Double
Explanation:
Since the period T of a pendulum is given by

By increasing the length of the pendulum by 4, the period becomes

You can see that the period doubles when we increase the length by a factor of 4.
answer is the color white