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 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.

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.

Which force causes the train to elevate upwards

A

Electrostatic force.

B

Time-varying electric field.

C

Magnetic force.

D

Induced electric field

3
IIT-JEE 2006
Numerical
+3
-0

There is a rectangular plate of mass M kg of dimensions ( $a \times b$ ). The plate is held in horizontal position by striking $n$ small balls each of mass m per unit area per unit time. These are striking in the shaded half region of the plate. The balls are colliding elastically with velocity $v$. What is $v$ ?

IIT-JEE 2006 Physics - Work Power & Energy Question 1 EnglishIt is given $n=100, \mathrm{M}=3 \mathrm{~kg}, m=0.01 \mathrm{~kg}$; $b=2 m ; a=1 \mathrm{~m} ; g=10 \mathrm{~m} / \mathrm{s}^2$
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4
IIT-JEE 2006
Numerical
+3
-0

In an insulated vessel, 0.05 kg steam at 373 K and 0.45 kg of ice at 253 K are mixed. Then, find the final temperature of the mixture.

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