# JEE (Advanced) 2013 Paper-2

Instructions

Following Questions of a paragraph has only one correct answer among the four choices(A), (B), (C) and (D).

The mass of a nucleus $$_{Z}^{A}X$$ is less than the sum of the masses of (A-Z) number of neutrons and Z number of protons in the nucleus. The energy equivalent to the corresponding mass difference is known as the binding energy of the nucleus. A heavy nucleus of mass M can break into two light nuclei of masses $$m_1$$ and $$m_2$$ only if $$(m_1 + m_2) < M$$. Also two light nuclei of masses $$m_3$$ and $$m_4$$ can undergo complete fusion and form a heavy nucleus of mass $$M'$$ only if $$(m_3 + m_4) > M'$$. The masses of some neutral atoms are given in the table below:

Question 11

Question 12

## The kinetic energy (in keV) of the alpha particle, when the nucleus $$^{210}_{84}Po$$ at rest undergoes alpha decay, is

Instructions

Following Questions of a paragraph has only one correct answer among the four choices(A), (B), (C) and (D).

A small block of mass 1 kg is released from rest at the top of a rough track. The track is a circular arc of radius 40 m. The block slides along the track without toppling and frictional force acts on it in the direction opposite to the instantaneous velocity. The work done in over coming the friction up to the point O, as shown in the figure below, is 150 J. (Take the acceleration due to gravity, g = 10m $$s^{-2}$$).

Question 13

Question 14

## The magnitude of the normal reaction that acts on the block at the point Q is

Instructions

A thermal power plant produces electric power of 600 kW at 4000 V, which is to be transported to a place 20 km away from the powerplant for consumersâ€™ usage. It can be transported either directly with a cable of large current carrying capacity or by using a combination of step-up and step-downtransformers at the two ends. The drawbackof the direct transmission is the large energy dissipation. In the method using transformers, the dissipation is much smaller. In this method, a step-up transformeris used at the plant side so that the current is reduced to a smaller value. At the consumersâ€™ end, a step-down transformer is used to supply powerto the consumersat the specified lower voltage. It is reasonable to assume that the powercable is purely resistive and the transformers are ideal with a powerfactor unity. All the currents and voltages mentioned are rms values.

Question 15

Question 16

## In the method using the transformers, assume that the ratio of the numberof turns in the primary to that in the secondary in the step-up transformeris 1 : 10. If the power to the consumers has to be supplied at 200 V, the ratio of the numberof turns in the primary to that in the secondary in the step-down transformer is

Instructions

For the following questions answer them individually

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Question 18

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Question 20