1
JEE Main 2021 (Online) 25th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Magnetic fields at two points on the axis of a circular coil at a distance of 0.05 m and 0.2 m from the centre are in the ratio 8 : 1. The radius of coil is ________.
A
1.0 m
B
0.15 m
C
0.2 m
D
0.1 m
2
JEE Main 2021 (Online) 25th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Match List - I with List - II :

List I List II
(a) h (Planck's constant) (i) $$[ML{T^{ - 1}}]$$
(b) E (kinetic energy) (ii) $$[M{L^2}{T^{ - 1}}]$$
(c) V (electric potential) (iii) $$[M{L^2}{T^{ - 2}}]$$
(d) P (linear momentum) (iv) $$[M{L^2}{I^{ - 1}}{T^{ - 3}}]$$


Choose the correct answer from the options given below :
A
(a) $$ \to $$ (ii), (b) $$ \to $$ (iii), (c) $$ \to $$ (iv), (d) $$ \to $$ (i)
B
(a) $$ \to $$ (i), (b) $$ \to $$ (ii), (c) $$ \to $$ (iv), (d) $$ \to $$ (iii)
C
(a) $$ \to $$ (iii), (b) $$ \to $$ (ii), (c) $$ \to $$ (iv), (d) $$ \to $$ (i)
D
(a) $$ \to $$ (iii), (b) $$ \to $$ (iv), (c) $$ \to $$ (ii), (d) $$ \to $$ (i)
3
JEE Main 2021 (Online) 25th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
Two radioactive substances X and Y originally have N1 and N2 nuclei respectively. Half life of X is half of the half life of Y. After three half lives of Y, number of nuclei of both are equal. The ratio $${{{N_1}} \over {{N_2}}}$$ will be equal to :
A
$${1 \over 8}$$
B
$${3 \over 1}$$
C
$${1 \over 3}$$
D
$${8 \over 1}$$
4
JEE Main 2021 (Online) 25th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Two satellites A and B of masses 200 kg and 400 kg are revolving round the earth at height of 600 km and 1600 km respectively.

If TA and TB are the time periods of A and B respectively then the value of TB $$-$$ TA :

JEE Main 2021 (Online) 25th February Morning Shift Physics - Gravitation Question 104 English
[Given : radius of earth = 6400 km, mass of earth = 6 $$\times$$ 1024 kg]
A
1.33 $$\times$$ 103 s
B
4.24 $$\times$$ 102 s
C
3.33 $$\times$$ 102 s
D
4.24 $$\times$$ 103 s
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