Electricity and Magnetism Answers

In the space surrounding a wire carrying a steady current, there exists
a magnetic field pointing radially outward
a magnetic field circling the wire
an oscillating magnatic field
no magnatic field

Kirchhof's junction rule is statement of conservation of -----------
mass
energy
charge
momentum

The term 'lost volts' refers to -----------
energy per coulomb dissipated in the external (load) resistance
terminal potential difference
energy per coulomb dissipated in the internal resistance of the source of emf
energy per coulomb wasted to heat up the connecting wires

A uniform electric field of 200 N/C is in the x-direction. A point charge of
3μC
3μC
is released from rest at the origin. What is the kinetic energy of the charge when it is at x = 4 m?

2.4×10−2J
2.4×10−2J

1.6×10−2J
1.6×10−2J

3.6×10−2J
3.6×10−2J

4.8×10−2J
4.8×10−2J

1 volt is equal to
1 watt/C
1 J/s C
1 J/C
1 N/C

The electric potential difference between two points A and B is 42 V. What is the work done by an external agent in carrying a charge of
5.0×10−5C
from A to B at constant speed?
2.1×10−3J
8.4×10−4J
21×10−4J
8.4×10−3J

Which of the following is not true about the electric field intensity
E⃗
of a uniformly charged solid sphere?
E⃗
is maximum at the surface of the sphere
E⃗
is directly proportional to the distance from the centre of the sphere
E⃗
decreases as a square of the distance from the surface of the sphere
E⃗
decreases as a square of the distance from the centre of the sphere.

From Gauss’ law which of the following is NOT correct?
The outward flux of electric field through an enclosed surface is proportional to the electric charges enclosed
The field at a point outside a spherically symmetric charge is the same as the electric field at the same point due to a point charge at its centre.
The electric flux through a Gaussian surface is a vector product of the electric field and a unit vector perpendicular to and outward from the surface
The total electric flux through a cylinder placed in an electric field with its axis parallel to the field is zero

Charges of
+2
+2
and
−2C
−2C
are situated at points P and Q respectively which are at a distance apart. A point X is mid-way between P and Q. Which of the following correctly describes the electric field and the electric potential at point X?
electric field is toward Q, electric potential is zero
electric field is toward Q, electric potential is negative
electric field is toward P, electric potential zero
electric field is toward P, electric potential is positive

A sodium ion (m=22.99g/mol, q=+1.6x10-19C) in the crystal structure of table sale lies .236nm from a chloride ion (35.45g/mol, q= -1.6x10-19C). Find the mutual force between the ions.