356274
Assertion : We use a thick wire in the secondary coil of a step down transformer to reduce the production of heat. Reason : When the plane of the armature is parallel to the line of force of magnetic field, the magnitude of induced \(e.m.f\) is maximum.
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:
A step-down transformer converts electrical energy from a high voltage to one at a low voltage. (Subscript \(p\) for primary and \(s\) for secondary) \(\Rightarrow V_{s} < V_{p}\) \(\Rightarrow I_{s}>I_{p}(\because P=V I=\) constant \()\) In order to produce less heat in secondary, we shall use a wire of less resistance and so "thick wire" (\(i.e.,\) \(r\) high in \(A=\pi r^{2}\) of formule \(\left.R=\rho \dfrac{l}{A}\right)\) radiation, \(\left(\dfrac{d \phi}{d t}\right)\) will be maximum when plane of armature is parallel to lines of force of magnetic field. (and then \(\left|V_{\text {ind }}\right|\) in maximum then).Both are facts, but assertion is true for a different explanation. So correct option is (2).
PHXII07:ALTERNATING CURRENT
356275
Assertion : A transformer cannot work on \(D C\) supply. Reason : \(D C\) changes neither in magnitude nor in direction.
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:
Transformers operate on the principle of electromagnetic induction, where a changing magnetic field in the primary coil induces a voltage in the secondary coil. In alternating current \((A C)\), the current regularly changes direction and magnitude, creating the necessary changing magnetic field for transformer action. However, direct current \((D C)\) remains constant in both magnitude and direction. So, 'Reason' accounts for 'Assertion'. So correct option is (1).
PHXII07:ALTERNATING CURRENT
356276
Statement A : A laminated core is used in transformers to increase eddy currents. Statement B : The efficiency of a transformer increases with increase in eddy currents.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both Statements are correct.
4 Both Statements are incorrect.
Explanation:
Large eddy currents are produced in non- laminated iron core of the trnasformer by the induced emf, as the resistance of bulk iron core is very small. Laminating the core substantially reduces the eddy currents. Eddy current heats up the core of the transformer. More the eddy currents greater is the loss of energy and the efficiency goes down.
356274
Assertion : We use a thick wire in the secondary coil of a step down transformer to reduce the production of heat. Reason : When the plane of the armature is parallel to the line of force of magnetic field, the magnitude of induced \(e.m.f\) is maximum.
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:
A step-down transformer converts electrical energy from a high voltage to one at a low voltage. (Subscript \(p\) for primary and \(s\) for secondary) \(\Rightarrow V_{s} < V_{p}\) \(\Rightarrow I_{s}>I_{p}(\because P=V I=\) constant \()\) In order to produce less heat in secondary, we shall use a wire of less resistance and so "thick wire" (\(i.e.,\) \(r\) high in \(A=\pi r^{2}\) of formule \(\left.R=\rho \dfrac{l}{A}\right)\) radiation, \(\left(\dfrac{d \phi}{d t}\right)\) will be maximum when plane of armature is parallel to lines of force of magnetic field. (and then \(\left|V_{\text {ind }}\right|\) in maximum then).Both are facts, but assertion is true for a different explanation. So correct option is (2).
PHXII07:ALTERNATING CURRENT
356275
Assertion : A transformer cannot work on \(D C\) supply. Reason : \(D C\) changes neither in magnitude nor in direction.
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:
Transformers operate on the principle of electromagnetic induction, where a changing magnetic field in the primary coil induces a voltage in the secondary coil. In alternating current \((A C)\), the current regularly changes direction and magnitude, creating the necessary changing magnetic field for transformer action. However, direct current \((D C)\) remains constant in both magnitude and direction. So, 'Reason' accounts for 'Assertion'. So correct option is (1).
PHXII07:ALTERNATING CURRENT
356276
Statement A : A laminated core is used in transformers to increase eddy currents. Statement B : The efficiency of a transformer increases with increase in eddy currents.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both Statements are correct.
4 Both Statements are incorrect.
Explanation:
Large eddy currents are produced in non- laminated iron core of the trnasformer by the induced emf, as the resistance of bulk iron core is very small. Laminating the core substantially reduces the eddy currents. Eddy current heats up the core of the transformer. More the eddy currents greater is the loss of energy and the efficiency goes down.
356274
Assertion : We use a thick wire in the secondary coil of a step down transformer to reduce the production of heat. Reason : When the plane of the armature is parallel to the line of force of magnetic field, the magnitude of induced \(e.m.f\) is maximum.
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:
A step-down transformer converts electrical energy from a high voltage to one at a low voltage. (Subscript \(p\) for primary and \(s\) for secondary) \(\Rightarrow V_{s} < V_{p}\) \(\Rightarrow I_{s}>I_{p}(\because P=V I=\) constant \()\) In order to produce less heat in secondary, we shall use a wire of less resistance and so "thick wire" (\(i.e.,\) \(r\) high in \(A=\pi r^{2}\) of formule \(\left.R=\rho \dfrac{l}{A}\right)\) radiation, \(\left(\dfrac{d \phi}{d t}\right)\) will be maximum when plane of armature is parallel to lines of force of magnetic field. (and then \(\left|V_{\text {ind }}\right|\) in maximum then).Both are facts, but assertion is true for a different explanation. So correct option is (2).
PHXII07:ALTERNATING CURRENT
356275
Assertion : A transformer cannot work on \(D C\) supply. Reason : \(D C\) changes neither in magnitude nor in direction.
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:
Transformers operate on the principle of electromagnetic induction, where a changing magnetic field in the primary coil induces a voltage in the secondary coil. In alternating current \((A C)\), the current regularly changes direction and magnitude, creating the necessary changing magnetic field for transformer action. However, direct current \((D C)\) remains constant in both magnitude and direction. So, 'Reason' accounts for 'Assertion'. So correct option is (1).
PHXII07:ALTERNATING CURRENT
356276
Statement A : A laminated core is used in transformers to increase eddy currents. Statement B : The efficiency of a transformer increases with increase in eddy currents.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both Statements are correct.
4 Both Statements are incorrect.
Explanation:
Large eddy currents are produced in non- laminated iron core of the trnasformer by the induced emf, as the resistance of bulk iron core is very small. Laminating the core substantially reduces the eddy currents. Eddy current heats up the core of the transformer. More the eddy currents greater is the loss of energy and the efficiency goes down.
356274
Assertion : We use a thick wire in the secondary coil of a step down transformer to reduce the production of heat. Reason : When the plane of the armature is parallel to the line of force of magnetic field, the magnitude of induced \(e.m.f\) is maximum.
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:
A step-down transformer converts electrical energy from a high voltage to one at a low voltage. (Subscript \(p\) for primary and \(s\) for secondary) \(\Rightarrow V_{s} < V_{p}\) \(\Rightarrow I_{s}>I_{p}(\because P=V I=\) constant \()\) In order to produce less heat in secondary, we shall use a wire of less resistance and so "thick wire" (\(i.e.,\) \(r\) high in \(A=\pi r^{2}\) of formule \(\left.R=\rho \dfrac{l}{A}\right)\) radiation, \(\left(\dfrac{d \phi}{d t}\right)\) will be maximum when plane of armature is parallel to lines of force of magnetic field. (and then \(\left|V_{\text {ind }}\right|\) in maximum then).Both are facts, but assertion is true for a different explanation. So correct option is (2).
PHXII07:ALTERNATING CURRENT
356275
Assertion : A transformer cannot work on \(D C\) supply. Reason : \(D C\) changes neither in magnitude nor in direction.
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:
Transformers operate on the principle of electromagnetic induction, where a changing magnetic field in the primary coil induces a voltage in the secondary coil. In alternating current \((A C)\), the current regularly changes direction and magnitude, creating the necessary changing magnetic field for transformer action. However, direct current \((D C)\) remains constant in both magnitude and direction. So, 'Reason' accounts for 'Assertion'. So correct option is (1).
PHXII07:ALTERNATING CURRENT
356276
Statement A : A laminated core is used in transformers to increase eddy currents. Statement B : The efficiency of a transformer increases with increase in eddy currents.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both Statements are correct.
4 Both Statements are incorrect.
Explanation:
Large eddy currents are produced in non- laminated iron core of the trnasformer by the induced emf, as the resistance of bulk iron core is very small. Laminating the core substantially reduces the eddy currents. Eddy current heats up the core of the transformer. More the eddy currents greater is the loss of energy and the efficiency goes down.
