JEE Main 2018 (Online) 15th April Morning Slot | Magnetics Question 217 | Physics

JEE Main 2018 (Online) 15th April Morning Slot

MCQ (Single Correct Answer)

-1

A Helmholtz coil has a pair of loops, each with $$N$$ turns and radius $$R$$. They are placed coaxially at distance $$R$$ and the same current $${\rm I}$$ flows through the loops in the same direction. $$P,$$ midway between the centers $$A$$ and $$C$$, is given by [Refer to figure given below] :

JEE Main 2018 (Online) 15th April Morning Slot Physics - Magnetics Question 227 English

JEE Main 2018 (Online) 15th April Morning Slot Physics - Magnetics Question 227 English

$${{8N{\mu _0}{\rm I}} \over {{5^{1/2}}R}}$$

$${{8N{\mu _0}{\rm I}} \over {{5^{3/2}}R}}$$

$${{4N{\mu _0}{\rm I}} \over {{5^{1/2}}R}}$$

$${{4N{\mu _0}{\rm I}} \over {{5^{3/2}}R}}$$

JEE Main 2018 (Online) 15th April Morning Slot

MCQ (Single Correct Answer)

-1

The $$B$$-$$H$$ curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solended with $$1000$$ turns/cm. The current that should be passed in the solended to demagnetise the ferromagnet completely is :

JEE Main 2018 (Online) 15th April Morning Slot Physics - Magnetics Question 226 English

JEE Main 2018 (Online) 15th April Morning Slot Physics - Magnetics Question 226 English

$$1$$ $$mA$$

$$2$$ $$mA$$

$$20\,\mu A$$

$$40\,\mu A$$

JEE Main 2017 (Online) 9th April Morning Slot

MCQ (Single Correct Answer)

-1

A negative test charge is moving near a long straight wire carrying a current. The force acting on the test charge is parallel to the direction of the current. The motion of the charge is :

away from the wire

towards the wire

parallel to the wire along the current

parallel to the wire opposite to the current

JEE Main 2017 (Online) 9th April Morning Slot

MCQ (Single Correct Answer)

-1

A uniform magnetic field B of 0.3 T is along the positive Z-direction. A rectangular loop (abcd) of sides 10 cm × 5 cm carries a current I of 12 A. Out of the followingdifferent orientations which one corresponds to stable equilibrium ?