Relative Strength of Magnetic Field Inferred from Magnetic Field Lines

Q.

Draw a diagram to show the magnetic field lines around a bar magnet.

Q.

The strength of magnetic field inside a long current carrying solenoid is :

1. found to increase from one end to the other.

2. minimum in the middle.

3. same at all points.

4. found to be maximum at the centre.

Q. A galvanometer has a coil resistance 100ohm and gives fsd of 30 mA if it is to work at voltmwtwr 30 V the resistance required is

Q.

When magnetic field lines are closer, the magnetic field is ___.

1. stronger

2. non-existent

3. weaker

4. random

Q.

What is the difference between the magnetic field and magnetic field lines?

Q. The current sensitivity of a moving coil galvanometer increases by 20% when its resistance is doubled. Calculate, by what factor does the voltage sensitivity change?(1) Becomes 3/5 times(2) Becomes 2/5 times(3) No change(4) Decreases by a factor of7/

Q.

If the key in the arrangement is taken out (the circuit is made open) and magnetic field lines are drawn over the horizontal plane ABCD, the lines are:

1. Elliptical in shape

2. Straight lines parallel to each other

3. Concentric circles near the point O but of elliptical shapes as we go away from it

4. Concentric circles

Q.

What is magnetic field line and its properties.

Q.

You are given the magnetic field pattern of a magnet. How will be find out from it where the magnetic field is the strongest ?

Q.

Why dont two magnetic lines of force intersect each other?

Q. How do you measure the relative strength of a magnetic field of an electromagnetic coil?

1. Calculate the density of iron filings at the edges
2. Calculate the size of the magnetic field produced
3. Use a multimeter to calculate the current flowing through the coil
4. Use a voltmeter to find the current flowing through the coil

Q.

Choose the incorrect statement from the following regarding magnetic lines of force:

1. The direction of magnetic field at a point is taken to be the direction in which the north pole of a magnetic compass needle points when placed at that point.

2. Magnetic field lines are closed curves.

3. If magnetic field lines are parallel and equidistant, they represent zero field strength.

4. Relative strength of magnetic field is shown by the degree of closeness of the field lines.

Q. Select the incorrect statement.

а) Magnetic field lines are closed curves
b) No two field lines can cross each other
c) Field lines can cross each other
d) The relative strength of the magnetic field is shown by degree of closness of the field lines.
[1 mark]

Q. Consider a short dipole. Let a be the electric field at a distance r from the axis, on the axial line. Let b be the electric field at a point at a distance r from the dipole measured along a line making angle with the dipole moment. If a is perpendicular to b then ( |a| / | b|) = n tan. Find n.

Q. 42.A long solenoid wire of radius a carries a steady current i.The Current is uniformly distributed across its cross section .The ratio of magnetic field at a/2 and 2a is

Q.

List the properties of magnetic lines of force. [3 MARKS]

Q. In an ammeter 0.2% of main current passes through the Galvanometer resistance of galvanometer is G the resistance of ammeter will be

Q.

The strength of magnetic field inside a long current carrying solenoid is :

1. found to increase from one end to the other.

2. minimum in the middle.

3. same at all points.

4. found to be maximum at the centre.

Q. Why the magnetic field at the ends points of a solenoid is half than it is in centre ?

Q.

The strength of magnetic field inside a long current carrying solenoid is :

1. minimum in the middle.

2. same at all points.

3. found to be maximum at the centre.

4. found to increase from one end to the other.

Q.

How to measure the intensity of a magnet?

Like we can measure current using ammeter...

Q. Assertion :The magnetic field at the centre of a circular loop carrying current is zero. Reason: Due to symmetry, the field produced by the diametrically opposite points add to each other.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect, but Reason is correct

Q. The number of turns per unit length of a long solenoid is 10. If the average radius is 5cm and it carries a current of 10A, then the ratio of flux densities obtained at the centre and at the end on the axis will be

Q. The resistance of a galvanometer coil is 48 Ω. What will be the resistance of shunt required to convert it into an ammeter of range 6 times as that of galvanometer?

Q. Why the magnetic field at the ends points of a solenoid is half than it is in centre ?

Q. In an AC generator, maximum number of lines of force pass though the coil when the angle between the plane of coil and lines of force is :

1. $0^{\circ }$
2. ${60}^{\circ }$
3. ${90}^{\circ }$
4. ${30}^{\circ }$

Q.

Magnetic lines of force

1. are mere directions

2. have no physical reality

3. can be used to indicate the direction of the magnetic field at a point

4. all the above are correct

Q.

Choose the incorrect statement from the following regarding magnetic lines of force:

1. The direction of magnetic field at a point is taken to be the direction in which the north pole of a magnetic compass needle points when placed at that point.

2. Magnetic field lines are closed curves.

3. If magnetic field lines are parallel and equidistant, they represent zero field strength.

4. Relative strength of magnetic field is shown by the degree of closeness of the field lines.

Q.

When magnetic field lines are closer, the magnetic field is ___.

1. stronger

2. non-existent

3. weaker

4. random