Magnetostatics

Q.

What are the 5 uses of magnets?

Q.

In a non uniform external field the dipole has a net force in the direction of increasing field when

1. 

2. 

3. 

4. none of these

Q. A wire having uniform linear charge density λ is placed in circular form in 3 quadrants with different polarities as shown in the figure. Let be the electric field at O. Then the angle made by with the line along y-axis is

Q. An electromagnetic wave can be deflected by -

1. an electric field.
2. a magnetic field.
3. Both options $\left(A\right)$ and $\left(B\right)$
4. neither electric field nor magnetic field.

Q.

What is the magnitude of magnetic force per unit length on a wire carrying a current of 8 A and making an angle of 30º with the direction of a uniform magnetic field of 0.15 T?

Q. The net electric force on a charge of +3μ C at the mid-point on the line joining two charges of magnitude+2 μ C and -2C separated by the distance of 6 mm is(a) 6000 N(c) 60 N(b) 500 N(d) zero

Q. If a copper rod carries a direct current, the magnetic field associated with the current will be present

1. inside the rod
2. outside the rod
3. on the surface of rod
4. only outside of the rod

Q. In the left hand rule, forefinger always represents

1. current
2. magnetic field
3. force

Q.

If the bar magnet in exercise 5.13 is turned around by 180º, where will the new null points be located?

Q.

The strength of the magnetic field generated at a given point around a straight conductor is directly proportional to the strength of the current flowing through it.

1. True
2. False

Q. Which of the following is/are true?

1. Magnetic field exerts force only on a moving charge.
2. Electric field exerts force on both stationary and moving charge.
3. Magnetic field exerts force on charge moving parallel to the direction of the field.
4. All the above

Q. A toroid is shown in the figure Find the correct option about the magnetic field at point $\text{A, B}$ and $\text{C}$.

1. $B_A=B_B$
2. $B_A=B_B=B_C$
3. $B_A=B_C$
4. $B_B=B_C=0$

Q.

To keep valuable instruments away from the earth's magnetic field, they are enclosed in iron boxes. Explain.

Q. An electron beam is moving from left to right of the observer, and the magnetic field is acting vertically upwards. The direction of the force acting on the electron is :-

1. Towards the observer
2. Downwards
3. Away from the observer
4. Upwards

Q. The magnetic field inside a toroid is uniform

1. True
2. False

Q. what is magnetic field due to long solid cylineder?

Q.

Name a device by which heavy loads of iron steel and iron scrap can be lifted.

Q. Gauss is unit of which quantity

1. Magnetic Field
2. Magnetic Flux Density
3. Resistance
4. Current

Q.

An electric dipole is placed in a non uniform electric field increasing along the $+ve$ direction of X - axis. The dipole moves along $\underset{–}{}$ and rotates $\underset{–}{}$

1. $+ve$ direction of X - axis, clockwise
2. $-ve$ direction of X - axis, clockwise
3. $+ve$ direction of X - axis, anti clockwise
4. $-ve$ direction of X - axis, anti clockwise

Q.

What is the magnitude of magnetic force per unit length on a wire carrying a current of 8 A and making an angle of 30º with the direction of a uniform magnetic field of 0.15 T?

Q. {A magnetic field of }(4.0×10^{-3}^ k)T exerts a }}{ force }(4.0i+3.0^ jj)×10^{-10}N on a particle having a charge }}10^{-9}C and moving in the x-y plane. Find the velocity of the } particle.

Q. 6.Name the electromagnetic unit and practical units of current . how they are related ?

Q. An electric current through a horizontal metal wire flowing from east to west direction, direction of magnetic field when the force is directed downward, is from

1. east to west
2. west to east
3. north to south
4. south to north

Q.

A horizontal overhead power line carries a current of 90 A in east to west direction. What is the magnitude and direction of the magnetic field due to the current 1.5 m below the line?

Q.

what is fleming right hand rule and fleming left hand rule?

Q.

A horizontal overhead power line carries a current of 90 A in east to west direction. What is the magnitude and direction of the magnetic field due to the current 1.5 m below the line?

Q. In the left hand rule, forefinger always represents

1. current
2. magnetic field
3. force

Q.

____________ itself is a gigantic magnet.

Q. A current of 10 A is established in a long wire along the positive z-axis. Find the magnetic field $\overrightarrow{B}$ at the point (1 m, 0, 0).

Q. Two positive charges q_2 and q_{3 }fixed along the y axis, exert a net electric force in the +x direction on a charge q_1 fixed along the x-axis. If a positive charge Q is added at (x, 0), the force on q_{1 }? (1)Shall increase along the positive x-axis (2)Shall decrease along the positive x-axis (3)Shall point along the negative x-axis