JEE Main 2016 (Online) 9th April Morning Slot | Magnetics Question 229 | Physics

JEE Main 2016 (Online) 9th April Morning Slot

MCQ (Single Correct Answer)

-1

A magnetic dipole is acted upon by two magnetic fields which are inclined to each other at an angle of 75^o. One of the fields has a magnitude of 15 mT. The dipole attains stable equilibrium at an angle of 30^o with this field. The magnitude of the other field (in mT ) is close to

1060

JEE Main 2016 (Online) 9th April Morning Slot

MCQ (Single Correct Answer)

-1

A 50 $$\Omega $$ resistance is connected to a battery of 5 V. A galvanometer of resistance 100 $$\Omega $$ is to be used as an ammeter to measure current through the resistance, for this a resistance r_s is connected to the galvanometer. Which of the following connections should be employed if the measured current is within 1% of thecurrent without the ammeter in the circuit ?

r_s = 0.5 $$\Omega $$ in parallel with the galvanometer

r_s = 0.5 $$\Omega $$ in series with the galvanometer

r_s = 1 $$\Omega $$ in series with galvanometer

r_s =1 $$\Omega $$ in parallel with galvanometer

JEE Main 2016 (Online) 9th April Morning Slot

MCQ (Single Correct Answer)

-1

To know the resistance G of a galvanometer by half deflection method, a battery of emf V_E and resistance R is used to deflect the galvanometer by angle $$\theta $$. If a shunt of resistance S is needed to get half deflection then G, R and S are related by the equation :

2S (R + G) = RG

S (R + G) = RG

2S = G

2G = S

JEE Main 2016 (Offline)

MCQ (Single Correct Answer)

-1

Two identical wires $$A$$ and $$B,$$ each of length $$'l'$$, carry the same current $$I$$. Wire $$A$$ is bent into a circle of radius $$R$$ and wire $$B$$ is bent to form a square of side $$'a'$$. If $${B_A}$$ and $${B_B}$$ are the values of magnetic fields at the centres of the circle and square respectively, then the ratio $${{{B_A}} \over {{B_B}}}$$ is:

$${{{\pi ^2}} \over {16}}$$

$${{{\pi ^2}} \over {8\sqrt 2 }}$$

$${{{\pi ^2}} \over {8}}$$

$${{{\pi ^2}} \over {16\sqrt 2 }}$$

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