1
IIT-JEE 2006
MCQ (Single Correct Answer)
+3
-1

Modern trains are based on Maglev technology in which trains are magnetically levitated, which runs its EDS Maglev system. There are coils on both sides of wheels. Due to motion of train, current induces in the coil of track which levitate it. This is in accordance with Lenz's law. If train lowers down, then according to Lenz's law, a repulsive force increases due to which train gets uplifted and if it goes much high then there is a net downward force due to gravity. The advantage of Maglev train is that there is no friction between the train and the track, thereby reducing the power consumption and enabling the train to attain very high speeds.

Disadvantages of Maglev train is that as it slows down, $t$ the electromagnetic forces decreases and it becomes difficult to keep levitated and as it moves forward according to Lenz law there is electromagnetic drag force.

What is the advantage of this system?

A

No friction hence no power consumption.

B

No electric power is used.

C

Gravitation force is zero.

D

Electrostatic force draws the train.

2
IIT-JEE 2006
MCQ (Single Correct Answer)
+3
-1

Modern trains are based on Maglev technology in which trains are magnetically levitated, which runs its EDS Maglev system. There are coils on both sides of wheels. Due to motion of train, current induces in the coil of track which levitate it. This is in accordance with Lenz's law. If train lowers down, then according to Lenz's law, a repulsive force increases due to which train gets uplifted and if it goes much high then there is a net downward force due to gravity. The advantage of Maglev train is that there is no friction between the train and the track, thereby reducing the power consumption and enabling the train to attain very high speeds.

Disadvantages of Maglev train is that as it slows down, $t$ the electromagnetic forces decreases and it becomes difficult to keep levitated and as it moves forward according to Lenz law there is electromagnetic drag force.

What is the disadvantage of this system?

A

Train experiences upward force according to Lenz's law

B

Friction force creates a drag on the train.

C

Retardation.

D

By Lenz's law, train experiences a drag.

3
IIT-JEE 2006
MCQ (Single Correct Answer)
+3
-1

Modern trains are based on Maglev technology in which trains are magnetically levitated, which runs its EDS Maglev system. There are coils on both sides of wheels. Due to motion of train, current induces in the coil of track which levitate it. This is in accordance with Lenz's law. If train lowers down, then according to Lenz's law, a repulsive force increases due to which train gets uplifted and if it goes much high then there is a net downward force due to gravity. The advantage of Maglev train is that there is no friction between the train and the track, thereby reducing the power consumption and enabling the train to attain very high speeds.

Disadvantages of Maglev train is that as it slows down, $t$ the electromagnetic forces decreases and it becomes difficult to keep levitated and as it moves forward according to Lenz law there is electromagnetic drag force.

Which force causes the train to elevate upwards

A

Electrostatic force.

B

Time-varying electric field.

C

Magnetic force.

D

Induced electric field

4
IIT-JEE 2005 Mains
MCQ (Single Correct Answer)
+3
-1

A long solenoid of radius a and number of turns per unit length $$n$$ is enclosed by cylindrical shell of radius R, thickness $$d$$ $$(d < < R)$$ and length L. A variable current $$\mathrm{I}=\mathrm{I}_{0} \sin \omega t$$ flows through the coil. If the resistivity of the material of cylindrical shell is $$\mathrm{P}$$, find the induced current in the shell.

IIT-JEE 2005 Mains Physics - Electromagnetic Induction Question 10 English

A
$$\mathrm{I}=\frac{\left(\mu_{0} \mathrm{~L} d n a^{2} \mathrm{I}_{0} \omega \cos \omega t\right)}{\rho \mathrm{R}}$$
B
$$\mathrm{I}=\frac{\left(3\mu_{0} \mathrm{~L} d n a^{2} \mathrm{I}_{0} \omega \cos \omega t\right)}{2 \rho \mathrm{R}}$$
C
$$\mathrm{I}=\frac{\left(\mu_{0} \mathrm{~L} d n a^{2} \mathrm{I}_{0} \omega \cos \omega t\right)}{2 \rho \mathrm{R}}$$
D
$$\mathrm{I}=\frac{3\left(\mu_{0} \mathrm{~L} d n a^{2} \mathrm{I}_{0} \omega \cos \omega t\right)}{ \rho \mathrm{R}}$$

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