360521
Assertion : Electromagnets are made of soft iron. Reason : Coercivity of soft iron is small.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Electro magnets are magnets only as long as current is passed through them. (They are not said to be permanent magnets, rather they are temporary magnets) Soft iron has two useful properties to be used in electromagnents. i) Small coercivity \(\left(H c^{\prime}\right)\) meaning that they can be easily magnetised and demagnetised. ii) For low \(H\) value, soft iron has high \(B\). So correct option is (1).
PHXII05:MAGNETISM and MATTER
360522
The \(B-H\) curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solenoid with 1000 turns/\(cm\). The current that should be passsed in the solenoid to demagnetise the ferromagnet completely is:
1 \(2 m A\)
2 \(20 \mu A\)
3 \(1 m A\)
4 \(40 \mu A\)
Explanation:
From the given graph Coercivity of Ferro magnet \(H = 100\;A/m\) \(nIH = 100\) \(I = \frac{{100}}{{{{10}^5}}} = 1\;mA\)
JEE - 2018
PHXII05:MAGNETISM and MATTER
360523
The coercive force for a certain permanent magnet is \(4 \times {10^4}A{m^{ - 1}}\). This magnet is placed in a long solenoid having 20 turns per \(cm\). The current to be passed to completely demagnetise it is
360521
Assertion : Electromagnets are made of soft iron. Reason : Coercivity of soft iron is small.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Electro magnets are magnets only as long as current is passed through them. (They are not said to be permanent magnets, rather they are temporary magnets) Soft iron has two useful properties to be used in electromagnents. i) Small coercivity \(\left(H c^{\prime}\right)\) meaning that they can be easily magnetised and demagnetised. ii) For low \(H\) value, soft iron has high \(B\). So correct option is (1).
PHXII05:MAGNETISM and MATTER
360522
The \(B-H\) curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solenoid with 1000 turns/\(cm\). The current that should be passsed in the solenoid to demagnetise the ferromagnet completely is:
1 \(2 m A\)
2 \(20 \mu A\)
3 \(1 m A\)
4 \(40 \mu A\)
Explanation:
From the given graph Coercivity of Ferro magnet \(H = 100\;A/m\) \(nIH = 100\) \(I = \frac{{100}}{{{{10}^5}}} = 1\;mA\)
JEE - 2018
PHXII05:MAGNETISM and MATTER
360523
The coercive force for a certain permanent magnet is \(4 \times {10^4}A{m^{ - 1}}\). This magnet is placed in a long solenoid having 20 turns per \(cm\). The current to be passed to completely demagnetise it is
360521
Assertion : Electromagnets are made of soft iron. Reason : Coercivity of soft iron is small.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Electro magnets are magnets only as long as current is passed through them. (They are not said to be permanent magnets, rather they are temporary magnets) Soft iron has two useful properties to be used in electromagnents. i) Small coercivity \(\left(H c^{\prime}\right)\) meaning that they can be easily magnetised and demagnetised. ii) For low \(H\) value, soft iron has high \(B\). So correct option is (1).
PHXII05:MAGNETISM and MATTER
360522
The \(B-H\) curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solenoid with 1000 turns/\(cm\). The current that should be passsed in the solenoid to demagnetise the ferromagnet completely is:
1 \(2 m A\)
2 \(20 \mu A\)
3 \(1 m A\)
4 \(40 \mu A\)
Explanation:
From the given graph Coercivity of Ferro magnet \(H = 100\;A/m\) \(nIH = 100\) \(I = \frac{{100}}{{{{10}^5}}} = 1\;mA\)
JEE - 2018
PHXII05:MAGNETISM and MATTER
360523
The coercive force for a certain permanent magnet is \(4 \times {10^4}A{m^{ - 1}}\). This magnet is placed in a long solenoid having 20 turns per \(cm\). The current to be passed to completely demagnetise it is
NEET Test Series from KOTA - 10 Papers In MS WORD
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PHXII05:MAGNETISM and MATTER
360521
Assertion : Electromagnets are made of soft iron. Reason : Coercivity of soft iron is small.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Electro magnets are magnets only as long as current is passed through them. (They are not said to be permanent magnets, rather they are temporary magnets) Soft iron has two useful properties to be used in electromagnents. i) Small coercivity \(\left(H c^{\prime}\right)\) meaning that they can be easily magnetised and demagnetised. ii) For low \(H\) value, soft iron has high \(B\). So correct option is (1).
PHXII05:MAGNETISM and MATTER
360522
The \(B-H\) curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solenoid with 1000 turns/\(cm\). The current that should be passsed in the solenoid to demagnetise the ferromagnet completely is:
1 \(2 m A\)
2 \(20 \mu A\)
3 \(1 m A\)
4 \(40 \mu A\)
Explanation:
From the given graph Coercivity of Ferro magnet \(H = 100\;A/m\) \(nIH = 100\) \(I = \frac{{100}}{{{{10}^5}}} = 1\;mA\)
JEE - 2018
PHXII05:MAGNETISM and MATTER
360523
The coercive force for a certain permanent magnet is \(4 \times {10^4}A{m^{ - 1}}\). This magnet is placed in a long solenoid having 20 turns per \(cm\). The current to be passed to completely demagnetise it is
360521
Assertion : Electromagnets are made of soft iron. Reason : Coercivity of soft iron is small.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Electro magnets are magnets only as long as current is passed through them. (They are not said to be permanent magnets, rather they are temporary magnets) Soft iron has two useful properties to be used in electromagnents. i) Small coercivity \(\left(H c^{\prime}\right)\) meaning that they can be easily magnetised and demagnetised. ii) For low \(H\) value, soft iron has high \(B\). So correct option is (1).
PHXII05:MAGNETISM and MATTER
360522
The \(B-H\) curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solenoid with 1000 turns/\(cm\). The current that should be passsed in the solenoid to demagnetise the ferromagnet completely is:
1 \(2 m A\)
2 \(20 \mu A\)
3 \(1 m A\)
4 \(40 \mu A\)
Explanation:
From the given graph Coercivity of Ferro magnet \(H = 100\;A/m\) \(nIH = 100\) \(I = \frac{{100}}{{{{10}^5}}} = 1\;mA\)
JEE - 2018
PHXII05:MAGNETISM and MATTER
360523
The coercive force for a certain permanent magnet is \(4 \times {10^4}A{m^{ - 1}}\). This magnet is placed in a long solenoid having 20 turns per \(cm\). The current to be passed to completely demagnetise it is
