JEE (Advanced) 2021 Paper 1
SECTION 1
This section contains FOUR (04) questions.
Each question has FOUR options (A), (B), (C) and (D). ONLY ONE of these four options is the correct
answer.
For each question, choose the option corresponding to the correct answer.
Answer to each question will be evaluated according to the following marking scheme:
Full Marks : +3 If ONLY the correct option is chosen;
Zero Marks : 0 If none of the options is chosen (i.e. the question is unanswered);
Negative Marks : −1 In all other cases.
Q.1 The smallest division on the main scale of a Vernier calipers is 0.1 cm. Ten
divisions of the Vernier scale correspond to nine divisions of the main scale. The
figure below on the left shows the reading of this calipers with no gap between its
two jaws. The figure on the right shows the reading with a solid sphere held
between the jaws. The correct diameter of the sphere is
(A) 3.07 cm (B) 3.11 cm (C) 3.15 cm (D) 3.17 cm
Q.2 An ideal gas undergoes a four step cycle as shown in the 𝑃 − 𝑉 diagram below.
During this cycle, heat is absorbed by the gas in
(A) steps 1 and 2 (B) steps 1 and 3
(C) steps 1 and 4 (D) steps 2 and 4
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,JEE (Advanced) 2021 Paper 1
Q.3 An extended object is placed at point O, 10 cm in front of a convex lens L1 and a
concave lens L2 is placed 10 cm behind it, as shown in the figure. The radii of
curvature of all the curved surfaces in both the lenses are 20 cm. The refractive index
of both the lenses is 1.5. The total magnification of this lens system is
(A) 0.4 (B) 0.8 (C) 1.3 (D) 1.6
Q.4 A heavy nucleus Q of half-life 20 minutes undergoes alpha-decay with probability of
60% and beta-decay with probability of 40%. Initially, the number of Q nuclei is
1000. The number of alpha-decays of Q in the first one hour is
(A) 50 (B) 75 (C) 350 (D) 525
2/11
, JEE (Advanced) 2021 Paper 1
SECTION 2
This section contains THREE (03) question stems.
There are TWO (02) questions corresponding to each question stem.
The answer to each question is a NUMERICAL VALUE.
For each question, enter the correct numerical value corresponding to the answer in the designated place
using the mouse and the on-screen virtual numeric keypad.
If the numerical value has more than two decimal places, truncate/round-off the value to TWO decimal
places.
Answer to each question will be evaluated according to the following marking scheme:
Full Marks : +2 If ONLY the correct numerical value is entered at the designated place;
Zero Marks : 0 In all other cases.
Question Stem for Question Nos. 5 and 6
Question Stem
A projectile is thrown from a point O on the ground at an angle 45° from the vertical and
with a speed 5√2 m/s. The projectile at the highest point of its trajectory splits into two
equal parts. One part falls vertically down to the ground, 0.5 s after the splitting. The other
part, 𝑡 seconds after the splitting, falls to the ground at a distance 𝑥 meters from the point
O. The acceleration due to gravity 𝑔 = 10 m/s2.
Q.5 The value of 𝑡 is ___ .
Q.6 The value of 𝑥 is ___ .
Question Stem for Question Nos. 7 and 8
Question Stem
In the circuit shown below, the switch S is connected to position P for a long time so
that the charge on the capacitor becomes 𝑞1 µC. Then S is switched to position Q.
After a long time, the charge on the capacitor is 𝑞2 µC.
3/11
SECTION 1
This section contains FOUR (04) questions.
Each question has FOUR options (A), (B), (C) and (D). ONLY ONE of these four options is the correct
answer.
For each question, choose the option corresponding to the correct answer.
Answer to each question will be evaluated according to the following marking scheme:
Full Marks : +3 If ONLY the correct option is chosen;
Zero Marks : 0 If none of the options is chosen (i.e. the question is unanswered);
Negative Marks : −1 In all other cases.
Q.1 The smallest division on the main scale of a Vernier calipers is 0.1 cm. Ten
divisions of the Vernier scale correspond to nine divisions of the main scale. The
figure below on the left shows the reading of this calipers with no gap between its
two jaws. The figure on the right shows the reading with a solid sphere held
between the jaws. The correct diameter of the sphere is
(A) 3.07 cm (B) 3.11 cm (C) 3.15 cm (D) 3.17 cm
Q.2 An ideal gas undergoes a four step cycle as shown in the 𝑃 − 𝑉 diagram below.
During this cycle, heat is absorbed by the gas in
(A) steps 1 and 2 (B) steps 1 and 3
(C) steps 1 and 4 (D) steps 2 and 4
1/11
,JEE (Advanced) 2021 Paper 1
Q.3 An extended object is placed at point O, 10 cm in front of a convex lens L1 and a
concave lens L2 is placed 10 cm behind it, as shown in the figure. The radii of
curvature of all the curved surfaces in both the lenses are 20 cm. The refractive index
of both the lenses is 1.5. The total magnification of this lens system is
(A) 0.4 (B) 0.8 (C) 1.3 (D) 1.6
Q.4 A heavy nucleus Q of half-life 20 minutes undergoes alpha-decay with probability of
60% and beta-decay with probability of 40%. Initially, the number of Q nuclei is
1000. The number of alpha-decays of Q in the first one hour is
(A) 50 (B) 75 (C) 350 (D) 525
2/11
, JEE (Advanced) 2021 Paper 1
SECTION 2
This section contains THREE (03) question stems.
There are TWO (02) questions corresponding to each question stem.
The answer to each question is a NUMERICAL VALUE.
For each question, enter the correct numerical value corresponding to the answer in the designated place
using the mouse and the on-screen virtual numeric keypad.
If the numerical value has more than two decimal places, truncate/round-off the value to TWO decimal
places.
Answer to each question will be evaluated according to the following marking scheme:
Full Marks : +2 If ONLY the correct numerical value is entered at the designated place;
Zero Marks : 0 In all other cases.
Question Stem for Question Nos. 5 and 6
Question Stem
A projectile is thrown from a point O on the ground at an angle 45° from the vertical and
with a speed 5√2 m/s. The projectile at the highest point of its trajectory splits into two
equal parts. One part falls vertically down to the ground, 0.5 s after the splitting. The other
part, 𝑡 seconds after the splitting, falls to the ground at a distance 𝑥 meters from the point
O. The acceleration due to gravity 𝑔 = 10 m/s2.
Q.5 The value of 𝑡 is ___ .
Q.6 The value of 𝑥 is ___ .
Question Stem for Question Nos. 7 and 8
Question Stem
In the circuit shown below, the switch S is connected to position P for a long time so
that the charge on the capacitor becomes 𝑞1 µC. Then S is switched to position Q.
After a long time, the charge on the capacitor is 𝑞2 µC.
3/11
