Answer:
c. may be accompanied by the sound of explosively expanding hot air, called thunder.
Explanation:
Lightning is a discharge which is due to the reaction between oppositely charged charges in the clouds, or between clouds base and the Earth surface.
The motion of the cloud causes charging of clouds by friction, thus the reaction between opposite charges (jumping of charges from one cloud to another) in the cloud can lead to lightning. Also, oftentimes the bottom of a cloud is negatively charged so that this is attracted to the positive charge on the earth surface. Thus leading to a discharge called lightning.
Thus in the given question, the appropriate option is C. This implies that, lightning may be accompanied by the sound of explosively expanding hot air, called thunder.
Answer:
Impedance, Z = 107 ohms
Explanation:
It is given that,
Resistance, R = 100 ohms
Inductance, 
Capacitance, 
Frequency, f = 60 Hz
Voltage, V = 120 V
The impedance of the circuit is given by :
...........(1)
Where
is the capacitive reactance, 

is the inductive reactance, 

So, equation (1) becomes :

Z = 106.26 ohms
or
Z = 107 ohms
So, the impedance of the circuit is 107 ohms. Hence, this is the required solution.
Answer:

Given:
Initial velocity (u) = 0 m/s (Starts from rest)
Final velocity (v) = 24 m/s
Time taken (t) = 6 seconds
To Find:
Distance travelled by car (s)
Explanation:
From equation of motion of object moving with uniform acceleration in straight line we have:

By substituting value of v, u & t in the equation we get:


Distance travelled by car (s) = 72 m
Answer:

Explanation:
The electrostatic attraction between the nucleus and the electron is given by:
(1)
where
k is the Coulomb's constant
Ze is the charge of the nucleus
e is the charge of the electron
r is the distance between the electron and the nucleus
This electrostatic attraction provides the centripetal force that keeps the electron in circular motion, which is given by:
(2)
where
m is the mass of the electron
v is the speed of the electron
Combining the two equations (1) and (2), we find

And solving for v, we find an expression for the speed of the electron:
