Answer:
Rate of change of area will be 
Explanation:
We have given rate of change of radius 
Radius of the circular plate r = 52 cm
Area is given by 
So 
Puting the value of r and 

So rate of change of area will be 
The correct answer is: They possess high concentrations of free electrons
The main characteristic of good conductors such as metals is the presence of movable electrically charged particles, or electrons. So, when an electric current is applied to a metal, the electrons will move and allow electricity to pass through them. Materials opposite of metals, with low electron mobility are not good conductors, instead they are called insulators.
Earth is the center according to the geocentric model.
Answer:
The circular loop experiences a constant force which is always directed towards the center of the loop and tends to compress it.
Explanation:
Since the magnetic field, B points in my direction and the current, I is moving in a clockwise direction, the current is always perpendicular to the magnetic field and will thus experience a constant force, F = BILsinФ where Ф is the angle between B and L.
Since the magnetic field is in my direction, it is perpendicular to the plane of the circular loop and thus perpendicular to L where L = length of circular loop. Thus Ф = 90° and F = BILsin90° = BIL
According to Fleming's left-hand rule, the fore finger representing the magnetic field, the middle finger represent in the current and the thumb representing the direction of force on the circular loop.
At each point on the circular loop, the force is always directed towards the center of the loop and thus tends to compress it.
<u>So, the circular loop experiences a constant force which is always directed towards the center of the loop and tends to compress it.</u>
Answer:
The temperature of air will increase by 
Explanation:
Given:
- no. of person in a theater,

- volume of air in the theater,

- rate of heat given off by each person,

- duration of movie,

- initial pressure in the theater,

- initial temperature in the theater,

- specific heat capacity of air at the given conditions,

<u>The total quantity of heat released by the total people in the theater during the movie:</u>



<u>Form the relation of heat capacity:</u>

∵



Change in temperature of air:
