1
JEE Main 2021 (Online) 24th February Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A circular hole of radius $$\left( {{a \over 2}} \right)$$ is cut out of a circular disc of radius 'a' as shown in figure. The centroid of the remaining circular portion with respect to point 'O' will be :

JEE Main 2021 (Online) 24th February Evening Shift Physics - Center of Mass and Collision Question 54 English
A
$${1 \over 6}a$$
B
$${2 \over 3}a$$
C
$${5 \over 6}a$$
D
$${10 \over 11}a$$
2
JEE Main 2021 (Online) 24th February Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Zener breakdown occurs in a p $$-$$ n junction having p and n both :
A
heavily doped and have wide depletion layer.
B
lightly doped and have narrow depletion layer.
C
heavily doped and have narrow depletion layer.
D
lightly doped and have wide depletion layer.
3
JEE Main 2021 (Online) 24th February Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The de-Broglie wavelength of a proton and $$\alpha$$-particle are equal. The ratio of their velocities is :
A
4 : 2
B
4 : 3
C
4 : 1
D
1 : 4
4
JEE Main 2021 (Online) 24th February Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
According to Bohr atomic model, in which of the following transitions will the frequency be maximum?
A
n = 2 to n = 1
B
n = 3 to n = 2
C
n = 4 to n = 3
D
n = 5 to n = 4
JEE Main Papers
2023
2021
EXAM MAP
Medical
NEET
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
CBSE
Class 12