NEET WEEKLY TEST PHYSICS (SDA KHATLA BRANCH) (05.09.2026)

1. A uniform disc of mass Mand radius R is rotating about an axis through its centre and perpendicular to plane. A small disc of mass M/2 and radius R/2 is removed, such that smaller disc is tangent internally to the original disc and its centre lies at a distance R/2 from the original centre. Find the moment of inertia of the remaining part about the original central axis?

2. A rectangular wooden block of length 5 m, width 1.5 m and height 0.5 m is placed gently on the surface of water. What will be the excess force required to take it away from the surface? Surface tension of water is 0.05 Nm^-1

3. A person is sitting on rotating chair and spinning with angular velocity ω. Initially, the person’s arms are stretched outward. He then pulls his arms close to his body. Assuming no external torque acts on the system, which statement is correct?

1. Moment of Inertia increases and Angular velocity decreases
2. Moment of Inertia decreases and Angular velocity increases
3. Both Moment of Inertia and Angular velocity are decreases
4. Both Moment of Inertia and Angular velocity are Increases

4. Water flows steadily through a pipe. At section A, the cross-sectional area is 6 cm², the pressure is 2.5×10⁵ Pa, and the speed of water is 2 ms^-1. Section B has a cross-sectional area of 2 cm² and is 3 m above section A. The pressure at section B is:

1. 1.84×10⁵ Pa
2. 2.04×10⁵  P  
3. 1.55×10⁵  Pa
4. 1.64×10⁵  Pa

5. If the distance of a particle from the axis is doubled, then its moment of inertia becomes

1. Half
2. 2 times
3. times
4. 4 times

6. A hollow sphere of total volume 1 m³ floats in water such that 3/4 th of its volume is submerged beneath the surface. If the density of water is 1000 kg m^-3 the mass of the hollow sphere is

1. 575 kg
2. 750 kg
3. 425 kg
4. 800 kg

7. If all the mass of a body is concentrated closer to the axis of rotation, its moment of inertia

1. Increases
2. Decreases
3. Remains same
4. Becomes infinite

8. The variation of excess pressure of a soap bubble with its radius is best represented by

9. A uniform rod of mass 4M and length L is bent uniformly into a complete circular ring. The moment of inertia of the ring about an axis passing through its centre and perpendicular to its plane is

10. If the mass of water rising in a capillary tube of radius 7 mm is 20 g, then height of the capillary rise will be approximately (density of water 1000 kg m^-3)

1. 8 cm
2. 13 cm
3. 18 cm
4. 20 cm

11. Two bodies have the same mass M and the same moment of inertia I about a given axis. Their radii of gyration are:

1. Always different
2. Always equal
3. Inversely proportional
4. Cannot be determined

12. If an air bubble of diameter 2 mm rises steadily through a liquid of density 2000 kg m^-3at a rate of 0.5 cms^-1, then the coefficient of viscosity of liquid (η) is ______ Poiseuille. (take g=10 ms^-2, neglect density of air)

1. 0.88
2. 8.88 
3. 88.8
4. 0.088

13. Two uniform circular discs have the same mass. Their radii are R₁=2R and R₂=αRThe ratio of their moments of inertia about their respective axes passing through the centres and perpendicular to their planes is I₁:I₂=1:20. The value of  is

1. 2√5
2. 4√5
3. 5√2
4. 5√4

14. A large cylindrical tank of radius 5 m and volume 750π m³, is completely filled with water. If a hole is made 10 m below the top of the tank, then time taken by water to reach the ground from the hole will be (g=10 ms^-2)

1. 2 s
2. 4 s
3. 6 s
4. 8 s

15. Assertion: The moment of inertia of a body is always independent of its angular velocity.
      Reason: Moment of inertia depends on mass distribution and the chosen axis, not on angular velocity.

1. Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
2. Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
3. Assertion is true, but Reason is false.
4. Assertion is false, but Reason is true.

16. The work done in blowing a soap bubble of surface tension 0.04 Nm^-1 from an initial diameter of to final diameter of  will be (use π=3.14)

1. 0.352 mJ
2. 0.704 mJ
3. 2.8 mJ
4. 1.4 mJ

17. Two particles of masses m and 2m are at distances r and 2r, respectively, from an axis. Their total moment of inertia is

1. 3mr²
2. 5mr²
3. 7mr²
4. 9mr²

18. A perfume spray nozzle has a main tube of diameter 1 cm. Fluid flows through this tube at a speed of 16 cms^-1 before being forced through 80 fine spray holes, each with a diameter Calculate the speed at which the perfume exits the spray holes.

1. 5 ms^-1
2. 10 ms^-1
3. 8 ms^-1
4. 16 ms^-1

19. The moment of inertia does not depend on

1. Mass of the body
2. Distribution of mass about the axis
3. Position of the axis of rotation
4. Angular velocity of the body

20. If the angle of contact is obtuse, which of the following is/are wrong?
A. Liquid will wet the walls of the tube
B. Water gets depressed down relative to the surface inside the tube
C. Meniscus will be concave

1. A only
2. A and C only
3. B and C only
4. C only

21. A body has moment of inertia about an axis. If its angular velocity is doubled, its moment of inertia becomes

1. I
2. 2I
3. 4I
4.  I/2

22. A liquid drop of mercury has a surface tension of 0.6 Nm^-1. If the excess pressure of the drop is 10 Pa, then the surface area of the drop (in cm²) will be

1. 576π
2. 169π
3. 144π
4. 484π

23. The photon radiated from hydrogen corresponding to the second line of Lyman series is absorbed by a hydrogen-like atom X in the second excited state. As a result, the hydrogen-like atom X makes a transition to n^th Then:

1. X = He⁺ , n=4
2. X = Li⁺⁺,n= 6
3. X = He⁺, n=9
4. X = Li⁺⁺,n= 9

24. For a nuclear fission process, suitable nuclei are

1. Any nuclei
2. Heavy nuclei
3. Lighter nuclei
4. Nuclei lying in the middle of periodic table

25. A square lamina of mass and side a has a moment of inertia about an axis passing through its centre and perpendicular to its plane equal to . What is its moment of inertia about an axis passing through one of its corners and perpendicular to its plane?

26. A hollow sphere of outer radius 10 cm and inner radius 8 cm is fully submerged in water. The buoyant force experienced by the sphere is
(density of water 1000 kg m^-3  ,g=10 ms^-2)

1. 3/4 π N
2.  8/3 π N       
3. 2/3 π N
4.  4/3 π N

27. A uniform rod of mass M and length L is rotating about an axis perpendicular to the rod. The axis is initially passing through its centre. If the axis is shifted by L/4, the percentage increase in moment of inertia is

1. 25%
2. 50%
3. 75%
4. 100%

28. Three identical point masses m are placed at three vertices of an equilateral triangle of side ‘a’. The moment of inertia about an axis passing through the centre of the triangle and perpendicular to its plane is

1. 1/2 ma²
2.  2/3 ma²
3. 3/2 ma²
4. ma²

29. The absolute pressure is defined as

1. Difference between atmospheric pressure and gauge pressure
2. Pressure at a depth
3. Sum of atmospheric and gauge pressure
4. Pressure above the surface i.e., atmospheric pressure

30. A uniform circular disc has moment of inertia I about an axis passing through its centre and perpendicular to its plane. If its moment of inertia about any diameter is I_d, then according to the perpendicular axis theorem

1. I_d=I
2. I_d=2I
3. I_d=I/2
4. I_d=I/4

31. If the specific weight of a liquid inside a cubical container of side 10 cm is 125 Nm^-3), then mass of that liquid will be g=10 ms^-2

1. 200 g
2. 125 g
3. 100 g
4. 150 g

32. From the following equations, pick out the possible nuclear reactions:

33. The radius of the orbit corresponding to the 4^th excited state in Li⁺⁺ ion is: (where a₀ is the radius of the first orbit in the hydrogen atom)

1. 25/3 a₀
2.  16/3 a₀
3. 25 a₀
4. 12 a₀

34. The frequencies of the series-limit of the Lyman & Balmer series of lines are ( ν_L and ν_B) respectively. Then, the frequency (ν_L-ν_B ) belongs to:

1. Lyman series
2. Balmer series
3. Paschen series
4. none of the above

35. The transition from the state n = 3 to n = 1 in hydrogen-like atoms results in ultraviolet radiation. Infrared radiation will be obtained in the transition from:

1. 3 → 2
2. 4 → 2
3. 4 → 3
4. 2 → 1

36. According to Bernoulli’s theorem, the pressure vs velocity of an incompressible horizontal fluid flow along a pipe is best represented by

37. The nuclear radius is given by R = R₀ A^1/3 where R₀ is constant and A is the atomic mass number. Then:

1. The nuclear mass density of U²³⁸is twice that of Sn¹¹⁹.
2. The nuclear mass density of U²³⁸ is thrice that of Sn¹¹⁹
3. The nuclear mass density of U²³⁸ is the same as that of Sn¹¹⁹
4. The nuclear mass density of U²³⁸ is half that of Sn¹¹⁹

38. The mass of a ₃Li⁷ nuclei is 0.042 u less than the sum of the masses of all its nucleons. The Binding energy per nucleon of ₃Li⁷  nucleus is nearly

1. 46 MeV
2. 5.6 MeV
3. 3.9 MeV
4. 2.3 MeV

39. If 1mg of U²³⁵ is completely annihilated, the energy liberated is

1. 9×10¹⁰ J
2. 9×10¹⁹ J
3. 9×10¹⁸ J
4. 9×10¹⁷  J

40. If an electron in a hydrogen atom jumps from the 3^rd orbit to the 2^nd orbit, it emits a photon of wavelength λ. When it jumps from the 4^th orbit to the 3^rd orbit, the corresponding wavelength of the photon will be:

1. 16/25 λ 
2. 9/16  λ                                
3. 20/7 λ
4. 20/13  λ

41. What is the frequency and wavelength of a photon emitted during a transition from n = 5 state to the n = 2 state in the hydrogen atom?

1 .6.91×10¹⁴  Hz, 434 nm                   
2.1.0×10¹⁴  Hz, 625 nm
3. 6.91×10¹⁴ Hz, 625 nm
4 .0.69 ×10¹⁴  Hz, 434 nm

42. The ratio of nuclear densities and nuclear volumes of and are, respectively:

1. 13:1 and 14:1
2. 14:1 and 1:1
3. 1:1 and 14:1
4. 1:1 and 13:1

43. Hydrogen atom in an excited state with (n=3) transitions directly to the ground state (n=1) emitting a single photon. Assuming the atom was initially at rest, what is the recoil velocity of hydrogen atom? (mass of H-atom =1.67×10^-27 kg)

1. 1.09 ms^-1
2. 3.86 ms^-1
3. 6.626 ms^-1
4. 10.2 ms^-1

44. In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change?

1. From n=2 to n=1
2. From n=3 to n=1
3. From n =4 to n=2
4. From n=7 to n=2

45. The binding energy per nucleon of deuteron 1.1 MeV and the binding energy per nucleon of helium is 7 MeV. If two deuterons are fused to form one then the energy released is

1. 23.6 MeV
2. 26.9 MeV
3. 19.2 MeV
4. 13.9 MeV