1
JEE Main 2024 (Online) 27th January Evening Shift
+4
-1

A current of $$200 \mu \mathrm{A}$$ deflects the coil of a moving coil galvanometer through $$60^{\circ}$$. The current to cause deflection through $$\frac{\pi}{10}$$ radian is :

A
120 $$\mu$$A
B
180 $$\mu$$A
C
30 $$\mu$$A
D
60 $$\mu$$A
2
JEE Main 2024 (Online) 27th January Evening Shift
+4
-1

Wheatstone bridge principle is used to measure the specific resistance $$\left(S_1\right)$$ of given wire, having length $$L$$, radius $$r$$. If $$X$$ is the resistance of wire, then specific resistance is ; $$S_1=X\left(\frac{\pi r^2}{L}\right)$$. If the length of the wire gets doubled then the value of specific resistance will be :

A
$$\frac{S_1}{4}$$
B
$$2 \mathrm{~S}_1$$
C
$$\frac{\mathrm{S}_1}{2}$$
D
$$S_1$$
3
JEE Main 2024 (Online) 27th January Morning Shift
+4
-1

A wire of length $$10 \mathrm{~cm}$$ and radius $$\sqrt{7} \times 10^{-4} \mathrm{~m}$$ connected across the right gap of a meter bridge. When a resistance of $$4.5 \Omega$$ is connected on the left gap by using a resistance box, the balance length is found to be at $$60 \mathrm{~cm}$$ from the left end. If the resistivity of the wire is $$\mathrm{R} \times 10^{-7} \Omega \mathrm{m}$$, then value of $$\mathrm{R}$$ is :

A
63
B
70
C
66
D
35
4
JEE Main 2024 (Online) 27th January Morning Shift
+4
-1

A wire of resistance $$\mathrm{R}$$ and length $$\mathrm{L}$$ is cut into 5 equal parts. If these parts are joined parallely, then resultant resistance will be :

A
$$\frac{1}{25} \mathrm{R}$$
B
$$\frac{1}{5} R$$
C
25 R
D
5 R
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