1
JEE Main 2024 (Online) 29th January Morning Shift
+4
-1

The electric current through a wire varies with time as $$I=I_0+\beta t$$, where $$I_0=20 \mathrm{~A}$$ and $$\beta=3 \mathrm{~A} / \mathrm{s}$$. The amount of electric charge crossed through a section of the wire in $$20 \mathrm{~s}$$ is :

A
80 C
B
800 C
C
1000 C
D
1600 C
2
JEE Main 2024 (Online) 27th January Evening Shift
+4
-1

Three voltmeters, all having different internal resistances are joined as shown in figure. When some potential difference is applied across $$A$$ and $$B$$, their readings are $$V_1, V_2$$ and $$V_3$$. Choose the correct option.

A
$$V_1=V_2$$
B
$$V_1 \neq V_3-V_2$$
C
$$V_1+V_2=V_3$$
D
$$V_1+V_2>V_3$$
3
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
4
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
$$S_1$$
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