JEE Main 2018 (Online) 15th April Evening Slot | Magnetic Effect of Current Question 182 | Physics

A current of 1 A is flowing on the sides of an equilateral triangle of side 4.5 $$ \times $$ 10^-2 m. The magnetic field at the center of the triangle will be :

2 $$ \times $$ 10^-5 Wb/m²

Zero

8 $$ \times $$ 10^-5 Wb/m²

4 $$ \times $$ 10^-5 Wb/m²

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 - Magnetic Effect of Current Question 186 English

JEE Main 2018 (Online) 15th April Morning Slot Physics - Magnetic Effect of Current Question 186 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 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) 8th April Morning Slot

MCQ (Single Correct Answer)

-1

A magnetic dipole in a constant magnetic field has :

maximum potential energy when the torque is maximum.

zero potential energy when the torque is minimum.

zero potential energy when the torque is maximum.

minimum potential energy when the torque is maximum.