PART I : PHYSICS
SECTION 1 (Maximum Marks: 28)
• This section contains SEVEN questions
• Each question has FOUR options [A], [B], [C] and [D]. ONE OR MORE THAN ONE of
these four options is(are) correct
• For each question, darken the bubble(s) corresponding to all the correct option(s) in the ORS
• For each question, marks will be awarded in one of the following categories:
Full Marks : +4 If only the bubble(s) corresponding to all the correct option(s)
is(are) darkened
Partial Marks : +1 For darkening a bubble corresponding to each correct option,
provided NO incorrect option is darkened
Zero Marks : 0 If none of the bubbles is darkened
Negative Marks : -2 In all other cases
• For example, if [A], [C] and [D] are all the correct options for a question, darkening all these
three will get +4 marks; darkening only [A] and [D] will get +2 marks; and darkening [A]
and [B] will get -2 marks, as a wrong option is also darkened
Q.1 A flat plate is moving normal to its plane through a gas under the action of a constant force
F. The gas is kept at a very low pressure. The speed of the plate v is much less than the
average speed u of the gas molecules. Which of the following options is/are true?
[A] The pressure difference between the leading and trailing faces of the plate is
proportional to uv
[B] The resistive force experienced by the plate is proportional to v
[C] The plate will continue to move with constant non-zero acceleration, at all times
[D] At a later time the external force F balances the resistive force
Space for rough work
Answer for the above question
Ans for Q.1: (A), (B), and (D)
3/36 Paper-1 Code 1
,Q.2 A block of mass M has a circular cut with a frictionless surface as shown. The block rests
on the horizontal frictionless surface of a fixed table. Initially the right edge of the block is
at x = 0, in a co-ordinate system fixed to the table. A point mass m is released from rest at
the topmost point of the path as shown and it slides down. When the mass loses contact
with the block, its position is x and the velocity is v. At that instant, which of the following
options is/are correct?
!"
[A] The position of the point mass m is: 𝑥 = − 2 !!!
!!"
[B] The velocity of the point mass m is: 𝑣 = !
!!
!
!"
[C] The x component of displacement of the center of mass of the block M is: − !!!
!
[D] The velocity of the block M is: 𝑉 = − ! 2𝑔𝑅
Space for rough work
Answer for the above question
Ans for Q.2: (B) and (C)
4/36 Paper-1 Code 1
,Q.3 A block M hangs vertically at the bottom end of a uniform rope of constant mass per unit
length. The top end of the rope is attached to a fixed rigid support at O. A transverse wave
pulse (Pulse 1) of wavelength λ0 is produced at point O on the rope. The pulse takes time
TOA to reach point A. If the wave pulse of wavelength λ0 is produced at point A (Pulse 2)
without disturbing the position of M it takes time TAO to reach point O. Which of the
following options is/are correct?
O Pulse 1
Pulse 2
A M
[A] The time TAO = TOA
[B] The velocities of the two pulses (Pulse 1 and Pulse 2) are the same at the midpoint of
rope
[C] The wavelength of Pulse 1 becomes longer when it reaches point A
[D] The velocity of any pulse along the rope is independent of its frequency and
wavelength
Space for rough work
Answer for the above question
Ans for Q.3: (A) and (D)
5/36 Paper-1 Code 1
, Q.4 A human body has a surface area of approximately 1 m! . The normal body temperature is
10 K above the surrounding room temperature 𝑇! . Take the room temperature to be
𝑇! = 300 K. For 𝑇! = 300 K, the value of 𝜎𝑇!! = 460 Wm!! (where 𝜎 is the Stefan-
Boltzmann constant). Which of the following options is/are correct?
[A] The amount of energy radiated by the body in 1 second is close to 60 Joules
[B] If the surrounding temperature reduces by a small amount ∆𝑇! ≪ 𝑇! , then to
maintain the same body temperature the same (living) human being needs to radiate
∆𝑊 = 4𝜎𝑇!! ∆𝑇! more energy per unit time
[C] Reducing the exposed surface area of the body (e.g. by curling up) allows humans to
maintain the same body temperature while reducing the energy lost by radiation
[D] If the body temperature rises significantly then the peak in the spectrum of
electromagnetic radiation emitted by the body would shift to longer wavelengths
Space for rough work
Answer for the above question
Ans for Q.4: (C)
6/36 Paper-1 Code 1
SECTION 1 (Maximum Marks: 28)
• This section contains SEVEN questions
• Each question has FOUR options [A], [B], [C] and [D]. ONE OR MORE THAN ONE of
these four options is(are) correct
• For each question, darken the bubble(s) corresponding to all the correct option(s) in the ORS
• For each question, marks will be awarded in one of the following categories:
Full Marks : +4 If only the bubble(s) corresponding to all the correct option(s)
is(are) darkened
Partial Marks : +1 For darkening a bubble corresponding to each correct option,
provided NO incorrect option is darkened
Zero Marks : 0 If none of the bubbles is darkened
Negative Marks : -2 In all other cases
• For example, if [A], [C] and [D] are all the correct options for a question, darkening all these
three will get +4 marks; darkening only [A] and [D] will get +2 marks; and darkening [A]
and [B] will get -2 marks, as a wrong option is also darkened
Q.1 A flat plate is moving normal to its plane through a gas under the action of a constant force
F. The gas is kept at a very low pressure. The speed of the plate v is much less than the
average speed u of the gas molecules. Which of the following options is/are true?
[A] The pressure difference between the leading and trailing faces of the plate is
proportional to uv
[B] The resistive force experienced by the plate is proportional to v
[C] The plate will continue to move with constant non-zero acceleration, at all times
[D] At a later time the external force F balances the resistive force
Space for rough work
Answer for the above question
Ans for Q.1: (A), (B), and (D)
3/36 Paper-1 Code 1
,Q.2 A block of mass M has a circular cut with a frictionless surface as shown. The block rests
on the horizontal frictionless surface of a fixed table. Initially the right edge of the block is
at x = 0, in a co-ordinate system fixed to the table. A point mass m is released from rest at
the topmost point of the path as shown and it slides down. When the mass loses contact
with the block, its position is x and the velocity is v. At that instant, which of the following
options is/are correct?
!"
[A] The position of the point mass m is: 𝑥 = − 2 !!!
!!"
[B] The velocity of the point mass m is: 𝑣 = !
!!
!
!"
[C] The x component of displacement of the center of mass of the block M is: − !!!
!
[D] The velocity of the block M is: 𝑉 = − ! 2𝑔𝑅
Space for rough work
Answer for the above question
Ans for Q.2: (B) and (C)
4/36 Paper-1 Code 1
,Q.3 A block M hangs vertically at the bottom end of a uniform rope of constant mass per unit
length. The top end of the rope is attached to a fixed rigid support at O. A transverse wave
pulse (Pulse 1) of wavelength λ0 is produced at point O on the rope. The pulse takes time
TOA to reach point A. If the wave pulse of wavelength λ0 is produced at point A (Pulse 2)
without disturbing the position of M it takes time TAO to reach point O. Which of the
following options is/are correct?
O Pulse 1
Pulse 2
A M
[A] The time TAO = TOA
[B] The velocities of the two pulses (Pulse 1 and Pulse 2) are the same at the midpoint of
rope
[C] The wavelength of Pulse 1 becomes longer when it reaches point A
[D] The velocity of any pulse along the rope is independent of its frequency and
wavelength
Space for rough work
Answer for the above question
Ans for Q.3: (A) and (D)
5/36 Paper-1 Code 1
, Q.4 A human body has a surface area of approximately 1 m! . The normal body temperature is
10 K above the surrounding room temperature 𝑇! . Take the room temperature to be
𝑇! = 300 K. For 𝑇! = 300 K, the value of 𝜎𝑇!! = 460 Wm!! (where 𝜎 is the Stefan-
Boltzmann constant). Which of the following options is/are correct?
[A] The amount of energy radiated by the body in 1 second is close to 60 Joules
[B] If the surrounding temperature reduces by a small amount ∆𝑇! ≪ 𝑇! , then to
maintain the same body temperature the same (living) human being needs to radiate
∆𝑊 = 4𝜎𝑇!! ∆𝑇! more energy per unit time
[C] Reducing the exposed surface area of the body (e.g. by curling up) allows humans to
maintain the same body temperature while reducing the energy lost by radiation
[D] If the body temperature rises significantly then the peak in the spectrum of
electromagnetic radiation emitted by the body would shift to longer wavelengths
Space for rough work
Answer for the above question
Ans for Q.4: (C)
6/36 Paper-1 Code 1
