Answer:
Inductive reactance is 125.7 Ω
Explanation:
It is given that,
Inductance, 
Voltage source, V = 15 volt
Frequency, f = 400 Hz
The inductive reactance of the circuit is equivalent to the impedance. It opposes the flow of electric current throughout the circuit. It is given by :




So, the inductive reactance is 125.7 Ω. Hence, this is the required solution.
Answer:

where E = electric field intensity
Explanation:
As we know that plastic ball is suspended by a string which makes 30 degree angle with the vertical
So here force due to electrostatic force on the charged ball is in horizontal direction along the direction of electric field
while weight of the ball is vertically downwards
so here we have


since string makes 30 degree angle with the vertical so we will have





where E = electric field intensity
2 times 10 to the power of 5 is your answer.
When sitting down there is gravity , when sat down the chair is pushing back at a equal but opposite force
It would be A:facing disagreement forces scientist to prove their theories more consistently :)