1
JEE Main 2020 (Online) 3rd September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A uniform magnetic field B exists in a direction perpendicular to the plane of a square loop made of a metal wire. The wire has a diameter of 4 mm and a total length of 30 cm. The magnetic field changes with time at a steady rate $${{dB} \over {dt}}$$ = 0.032 Ts–1. The induced current in the loop is close to (Resistivity of the metal wire is 1.23 $$ \times $$ 10–8 $$\Omega $$m)
A
0.53 A
B
0.43 A
C
0.34 A
D
0.61 A
2
JEE Main 2020 (Online) 3rd September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
To raise the temperature of a certain mass of gas by 50oC at a constant pressure, 160 calories of heat is required. When the same mass of gas is cooled by 100oC at constant volume, 240 calories of heat is released. How many degrees of freedom does each molecule of this gas have (assume gas to be ideal)?
A
6
B
7
C
5
D
3
3
JEE Main 2020 (Online) 3rd September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Concentric metallic hollow spheres of radii R and 4R hold charges Q1 and Q2 respectively. Given that surface charge densities of the concentric spheres are equal, the potential difference V(R) – V(4R) is :
A
$${{3{Q_2}} \over {4\pi {\varepsilon _0}R}}$$
B
$${{3{Q_1}} \over {4\pi {\varepsilon _0}R}}$$
C
$${{3{Q_1}} \over {16\pi {\varepsilon _0}R}}$$
D
$${{{Q_2}} \over {4\pi {\varepsilon _0}R}}$$
4
JEE Main 2020 (Online) 3rd September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A perfectly diamagnetic sphere has a small spherical cavity at its centre, which is filled with a paramagnetic substance. The whole system is placed in a uniform magnetic field $$\overrightarrow B $$ . Then the field inside the paramagnetic substance is : JEE Main 2020 (Online) 3rd September Evening Slot Physics - Magnetic Properties of Matter Question 40 English
A
$$\overrightarrow B $$
B
zero
C
much large than $$\left| {\overrightarrow B } \right|$$ and parallel to $$\overrightarrow B $$
D
much large than $$\left| {\overrightarrow B } \right|$$ but opposite to $$\overrightarrow B $$
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