The transition temperature at which all the ferromagnetic materials become paramagnetic materials is termed as the 'Curie temperature'. Its value for cobalt is __________ °C.

Consider the following statements: 1. Both ferromagnetic and ferrimagnetic materials have domain structures; each domain has randomly oriented magnetic moments when no external field is applied. 2. Both ferromagnetic and ferrimagnetic materials make those domains that have a favourable orientation to the applied field grow in size. 3. The net magnetic moment in ferromagnetic materials is higher than that in ferrimagnetic materials. 4. The net magnetic moment in ferrimagnetic materials is higher than that in ferromagnetic material. Which of the above statements are correct?

A

1 and 4 only

B

1, 2 and 4

C

2 and 4 only

D

1, 2 and 3

Assertion (A) The ferromagnetic substances do not obey Curie's law.
Reason (R) At Curie point a ferromagnetic substance start behaving as a paramagnetic substance.

A

Both A and R are true and R is the correct explanation of A

B

Both A and R are true, but R is not the correct explanation of A

C

A is true, but R is false

D

A is false, but R is true

Consider the following statements regarding a ferromagnetic material: 1. Below the ferromagnetic Curie temperature, the ferromagnetic materials exhibit a hysteresis effect. 2. The coercive force is the field required to reduce the flux density to zero. Which of the above statements is/are correct?

A

Both 1 and 2

B

Neither 1 nor 2

C

1 only

D

2 only

Consider the following statements regarding properties of ferromagnetic domains 1. Permanent magnetization 2. Above Curie temperature, domains disrupt 3. Each domain is magnetically saturated 4. Atomic moments in individual domains are all aligned neither parallel to nor perpendicular to one another below Curie temperature. Which of the above statements are correct?

A

1, 2 and 3 only

B

1 and 3 only

C

2 and 4 only

D

3 and 4 only

Find the susceptibility when the curie constant is 0.2 and the difference in critical temperature and paramagnetic curie temperature is 0.01.

A

2

B

20

C

0.02

D

200

Two statements are given followed by two conclusions as responses. You have to consider the statements to be true even if they seem to be at variance from the commonly known facts. You have to decide which of the given conclusion(s) can definitely be drawn from the given statements. Statements: There was a time when the world believed that women cannot be as good as men due to the gender stereotypes that existed in the society. Marie Curie turned out to be an excellent scientist and was the first person to win the Nobel Prize twice. Conclusions: Marie Curie broke the gender stereotypes by turning out to be better than men. Marie Curie wanted to win the Nobel Prize.

A

Only Conclusion I follows.

B

Only Conclusion II follows.

C

Both the Conclusions I and II follow.

D

Neither Conclusion I nor II follows.

Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it.
Modern civilization is completely dependent on energy, which has therefore to be abundant and also economical. About 85% of the world's energy is supplied by oil, coal and natural gas while nuclear, hydro, wind and solar power and biomass supply the rest. Coal, nuclear and hydro are used primarily to generate electricity while natural gas is widely used for heating. Biomass is used both for heating and cooking. The wind and solar power is the future's hope as they are sustainable energy sources. Oil powers almost all machines that move and that makes oil uniquely versatile. Oil powered airplanes carry 500 people across the widest oceans at nearly the speed of sound. Oil powered machines produce and transport food. Oil powered machines are ubiquitous. Clearly, we live in the age of oil but it is drawing to a close. According to data available if oil production remains constant until it's gone, there is enough to last 42 years. Oil wells will produce less as they become depleted, which will make it impossible to keep production constant. Similarly natural gas and coal will last another 61 years and 133 years respectively. Naturally, as they become scarce, they become expensive, leading to a worldwide energy crisis. If we are to survive on this planet, we have to make a transition to sustainable energy sources. The transition may be willy-nilly or planned - the choice is ours. The dawning era of limited and expensive energy will be very difficult for everyone on earth but will be even more difficult if it is not anticipated. It is of utmost importance that the public and policymakers understand the global energy crisis and act in tandem to ensure that the species 'homo sapiens' does not become extinct. The theme of the passage is

A

Changing Lives

B

Looming Energy Crisis

C

Energy Resources

D

Power in Today's world

Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it.
Modern civilization is completely dependent on energy, which has therefore to be abundant and also economical. About 85% of the world's energy is supplied by oil, coal and natural gas while nuclear, hydro, wind and solar power and biomass supply the rest. Coal, nuclear and hydro are used primarily to generate electricity while natural gas is widely used for heating. Biomass is used both for heating and cooking. The wind and solar power is the future's hope as they are sustainable energy sources. Oil powers almost all machines that move and that makes oil uniquely versatile. Oil powered airplanes carry 500 people across the widest oceans at nearly the speed of sound. Oil powered machines produce and transport food. Oil powered machines are ubiquitous. Clearly, we live in the age of oil but it is drawing to a close. According to data available if oil production remains constant until it's gone, there is enough to last 42 years. Oil wells will produce less as they become depleted, which will make it impossible to keep production constant. Similarly natural gas and coal will last another 61 years and 133 years respectively. Naturally, as they become scarce, they become expensive, leading to a worldwide energy crisis. If we are to survive on this planet, we have to make a transition to sustainable energy sources. The transition may be willy-nilly or planned - the choice is ours. The dawning era of limited and expensive energy will be very difficult for everyone on earth but will be even more difficult if it is not anticipated. It is of utmost importance that the public and policymakers understand the global energy crisis and act in tandem to ensure that the species 'homo sapiens' does not become extinct. Biomass is an energy source used in

A

agriculture

B

industry

C

homes

D

offices

Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it.
Modern civilisation is completely dependent on energy, which has therefore to be abundant and also economical. About 85% of the world's energy is supplied by oil, coal and natural gas while nuclear, hydro, wind and solar power and biomass supply the rest. Coal, nuclear and hydro are used primarily to generate electricity while natural gas is widely used for heating. Biomass is used both for heating and cooking. The wind and solar power is the future's hope as they are sustainable energy sources. Oil powers almost all machines that move and that makes oil uniquely versatile. Oil powered airplanes carry 500 people across the widest oceans at nearly the speed of sound. Oil powered machines produce and transport food. Oil powered machines are ubiquitous. Clearly, we live in the age of oil but it is drawing to a close. According to data available if oil production remains constant until it's gone, there is enough to last 42 years. Oil wells will produce less as they become depleted, which will make it impossible to keep production constant. Similarly natural gas and coal will last another 61 years and 133 years respectively. Naturally, as they become scarce, they become expensive, leading to a worldwide energy crisis. If we are to survive on this planet, we have to make a transition to sustainable energy sources. The transition may be willy-nilly or planned - the choice is ours. The dawning era of limited and expensive energy will be very difficult for everyone on earth but will be even more difficult if it is not anticipated. It is of utmost importance that the public and policymakers understand the global energy crisis and act in tandem to ensure that the species 'homo sapiens' does not become extinct. The synonym for Ubiquitous is

A

Omnipotent

B

Omnifarious

C

Omniscient

D

Omnipresent

Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it.
Modern civilisation is completely dependent on energy, which has therefore to be abundant and also economical. About 85% of the world's energy is supplied by oil, coal and natural gas while nuclear, hydro, wind and solar power and biomass supply the rest. Coal, nuclear and hydro are used primarily to generate electricity while natural gas is widely used for heating. Biomass is used both for heating and cooking. The wind and solar power is the future's hope as they are sustainable energy sources. Oil powers almost all machines that move and that makes oil uniquely versatile. Oil powered airplanes carry 500 people across the widest oceans at nearly the speed of sound. Oil powered machines produce and transport food. Oil powered machines are ubiquitous. Clearly, we live in the age of oil but it is drawing to a close. According to data available if oil production remains constant until it's gone, there is enough to last 42 years. Oil wells will produce less as they become depleted, which will make it impossible to keep production constant. Similarly natural gas and coal will last another 61 years and 133 years respectively. Naturally, as they become scarce, they become expensive, leading to a worldwide energy crisis. If we are to survive on this planet, we have to make a transition to sustainable energy sources. The transition may be willy-nilly or planned - the choice is ours. The dawning era of limited and expensive energy will be very difficult for everyone on earth but will be even more difficult if it is not anticipated. It is of utmost importance that the public and policymakers understand the global energy crisis and act in tandem to ensure that the species 'homo sapiens' does not become extinct. The energy sources of the future are

A

nuclear and hydro power

B

coal and natural gas

C

wind and solar power

D

oil and biomass

The transition temperature at which all the ferromagnetic materials become paramagnetic materials is termed as the 'Curie temperature'. Its value for cobalt is __________ °C.

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