Answer:
The speed of the wire is 5 m/s.
Explanation:
Given that,
Length = 20 cm
Magnetic field = 0.1 T
Current = 10 mA
Resistance 
We need to calculate the speed of the wire
Using formula of emf

Using formula of current

Put the value of
into the formula of current




Hence, The speed of the wire is 5 m/s.
Answer:

Explanation:
Electrostatic Forces
The force exerted between two point charges
and
separated a distance d is given by Coulomb's formula

The forces are attractive if the charges have different signs and repulsive if they have equal signs.
The problem described in the question locates three point charges in a straight line. The charges have the values shown below


The distance between
and
is

The distance between
and
is

We must find the value of
such that

Applying Coulomb's formula for
is

Now for 

If the total force on
is zero, both forces must be equal. Note that being q2 negative, the force on q3 is to the right. The force exerted by q1 must go to the left, thus q1 must be positive. Equating the forces we have:


Simplfying and solving for 



At 8:00 pm, the velocity of the storm is 55 mi northeast. Assuming that the direction is exactly northeast, the angle is 45°
At 11:00 pm, the velocity is 75 mi north. The angle is 90°
In vector form
55 ∠ 45°
and
75 ∠ 90°
The magnitude and direction of the average velocity is
(55 ∠ 45° + 75 ∠ 90° ) / 3
Answer:
electronic communications may be disrupted
Explanation:
Solar Flares: They occur when the magnetic field lines carrying charged particle entangle and reorganize over the photosphere of the Sun. In these flares charged particles leave the surface of the Sun to travel outwards.
If these flares are directed towards Earth, they will interact with anything related to electricity and magnetism. Out of the given options third option is correct as the electronic communication will be disrupted. If the flares are strong a complete power blackout may occur and that would disrupt all the communication channel and power transmission. Such events have occurred in the past as well.