Magnetic effect of current

Magnetic effect of current

Open Ended

A charge is placed at rest at a point P whose coordinates are (2,3,0) and a magnetic field B = 5 x 10^-3 k is present there. What is the magnetic force experienced by the charge?

zero

charge particle at rest

Open Ended

An electron enters a given region moving with an initial velocity v = 12.5i m/s where a uniform magnetic field B= B₀j is also applied. What is the direction of force experienced by electron due to the magnetic field?

Open Ended

Under what conditions does a moving charge experience minimum force due to a magnetic field present there?

no or minimum force

when v is either parallel or antiparallel to B

Open Ended

Under what conditions does a moving charge experience maximum force due to a magnetic field present there?

Open Ended

Why do we use a radial magnetic field?

torque= NIABsin $\theta$   

radial makes angles always 90 degree so max torque

Open Ended

There is a moving coil galvanometer in which there are 30 divisions on either side of central zero mark. It gives full scale deflection for a current of 600μA. What is its current sensitivity?

I_s= Ø/I

=30/600 x 10^-6 = 5 x 10⁴ div/A

Open Ended

If you want to measure a current ranging 0-1.5A using galvanometer. What shunt resistance should be joined with it? Resistance of the galvanometer coil is 300Ω.

300x 600 x 10^-6/(1.5-(600 x 10^-6))=

0.12ohm

Open Ended

What is the net resistance of the shunted galvanometer?

net resistance= r_sR_G/( r_s + R_G)

0.12 x 300/ (0.12 +300)= 0.12ohm

Multiple Choice

Assertion-An ammeter is connected in series of the current carrying circuit but a voltmeter is connected in parallel across those two points, pd between which is to be measured.

Reason- Resistance of an ideal ammeter is zero but the resistance of an ideal voltmeter is infinite.

• a)If both assertion and reason true and reason is correct explanation of assertion.

• b)If both assertion and reason true but the reason is not the correct explanation of assertion.

• c)If assertion is true but reason is false

• d)If the assertion is false but reason is true.

Multiple Choice

Assertion- If a proton and an alpha particle enter a uniform magnetic field normally with the same velocity, the time period of revolution of the alpha particle is double than that of the proton.

Reason- In a magnetic field the time period of revolution of a charged particle is directly proportional to its mass.

• a)If both assertion and reason true and reason is correct explanation of assertion.

• b)If both assertion and reason true but reason is not correct explanation of assertion.

• c) If assertion is true but reason is false

• d)If assertion is false but reason is true

Open Ended

Calculate the force per unit length on a long straight wire carrying current of 4A due to a parallel wire carrying 6A current. Distance between the wires is 3cm.

Force/length= μ₀ 2 I₁ I₂/4πd

1.6 x 10^-4 T

Multiple Choice

A proton (or an electron) is moving in a uniform magnetic field. What is the path of the proton (or an electron) if it enters parallel to the field.

• circular

• straight line

• helix

Multiple Choice

A square coil of side 10cm has 20 turns and carries a current of 12 A. The coil is suspended vertically. The normal to the plane of the coil makes an angle of 30⁰ with the direction of a uniform horizontal magnetic field. If the torque experienced by the coil equals 0.96Nm, find the magnitude of the magnetic field.

• 0.6T

• 0.7T

• 0.8T

torque= NIABsinΦ

B= 0.8T