Physicial Science – WBSSC 2nd SLST(AT) 2025 IX-X

WBSSC 2nd SLST Question Paper – 2025

1. The catalyst used in Friedel-Craft’s reaction is

(A) Anhydrous aluminium chloride

(B) Sodium nitrate

(C) Potassium hydroxide

(D) Copper sulfate

2. The refractive index of water and glass are ⁴/₃ and ⁵/₃ respectively. What will be the critical angle for the ray of light entering water from glass?

(A) sin⁻¹(⁴/₅)

(B) sin⁻¹(⁵/₄)

(C) sin⁻¹(¹/₂)

(D) sin⁻¹(¹/₃)

3. The expression for average velocity of gas molecules obeying kinetic theory of gases is (T=temperature in Kelvin Scale, M=molar mass)

(A) √(2RT/M)

(B) √(3RT/M)

(C) √(8RT/M)

(D) √(8RT/πM)

4. An A.C. Voltmeter measures

(A) peak value of voltage

(B) root mean square value of voltage

(C) instantaneous value of voltage

(D) average value of voltage

5. In a transistor, when the saturation current is reached, the value of resistance is

(A) zero

(B) constant and finite

(C) infinite

(D) None of the above

6. Which of the following salt solutions will have the same value of Van’t Hoff factor as that of K₄[Fe(CN)₆] solution at infinite dilution?

(A) Al₂(SO₄)₃

(B) NaCl

(C) K₃[Fe(CN)₆]

(D) Na₂SO₄

7. For sustaining oscillations in an electronic oscillator,

(A) Feedback factor should be unity

(B) Feedback factor should be negative

(C) Phase shaft should be zero

(D) Both options (A) and (C) are correct

8. Which of the following compounds on treatment with NaHCO₃, liberates CO₂?

(A) Acetic acid

(B) Ethyl amine

(C) Acetone

(D) Ethyl alcohol

9. When hydrogen nuclei is bombarded with a neutron, it forms

(A) Alpha particle

(B) Deuterium

(C) Beta particle

(D) Tritium

10. Aspirin is produced by heating Salicylic acid with

(A) Acetic anhydride and Phosphoric acid

(B) Benzoic anhydride and Phosphoric acid

(C) Methyl alcohol and Sulphuric acid

(D) Phenol and Sulphuric acid

11. Among the following, the electronic configuration of inert element is

(A) 1s²2s¹

(B) 1s²2s²2p⁶3s²3p⁶

(C) 1s²2s²2p⁵

(D) 1s²2s²2p⁶3s²3p⁶4s¹

12. A flask containing air at 27°C temperature and one atmospheric pressure is corked up. A pressure of 2.5 atmospheres inside the flask would force the cork out. This happens at a temperature of

(A) 67.5°C

(B) 750°C

(C) 477°C

(D) 670°C

13. The Compton shift of wavelength is maximum when the photon is scattered at an angle θ. The value of θ is

(A) 0°

(B) 45°

(C) 90°

(D) 180°

14. In relation of pressure (P) and volume (V) for an adiabatic reversible change of an ideal gas is [γ=Cₚ/Cᵥ]

(A) PV¹⁻ᵞ=constant

(B) PVᵞ=constant

(C) P¹⁻ᵞV=constant

(D) PᵞV¹⁻ᵞ=constant

15. The wavelength of the Kα line of X-Ray emitted from an anti-cathode made up of an element of atomic number Z is proportional to

(A) Z²

(B) (Z-1)²

(C) 1/(Z-1)²

(D) 1/(Z-1)

16. A bullet of mass 25 gm moving with a velocity of 200 cm/s is stopped within 5 cm of the target. The average resistance offered by the target is

(A) 1 N

(B) 2 N

(C) 3 N

(D) 4 N

17. If two waves having same amplitude and frequency superpose to produce a resultant wave of same amplitude, the waves differ in phase by

(A) π

(B) 2π/3

(C) π/3

(D) 3π

18. A lens behaves as a converging lens in air and a diverging lens in water. The refractive index of the material of the lens is

(A) µ=1

(B) µ=1.33

(C) 1<µ<1.33

(D) µ>1.33

19. 16 grams of oxygen gas and x grams of hydrogen gas occupies the same volume at the same temperature and pressure. The value of x is

(A) 1 gram

(B) 2 grams

(C) 3 grams

(D) 4 grams

20. The pH of 0.01 (M) NaOH solution at 25°C is

(A) 1

(B) 0

(C) 7

(D) 12

21. In the following reaction X and Y are:
    

(A) PhCH₂OH and PhCOOH

(B) PhCH₂OH and PhCH₃

(C) PhCH₃ and PhCOOH

(D) Benzene and PhCOOH

22. A particle moves in such a way that its acceleration a is given by a = -bx (where b is a constant and x is displacement from equilibrium position). The time period of oscillatory motion of the particle is

(A) 2π/√b

(B) √2π/b

(C) 2π/b

(D) 2√(π/b)

23. Which of the following acids is not responsible for acid rain?

(A) CH₃COOH

(B) H₂SO₄

(C) H₂SO₃

(D) HNO₃

24. The electronic energy for n-th Bohr orbit of a hydrogen atom is

(A) -13.6/n⁴ eV

(B) -13.6/n³ eV

(C) -13.6/n² eV

(D) -13.6/n eV

25. A liquid with coefficient of volume expansivity γ is filled in a container of material having coefficient of linear expansion α. If the liquid overflows on heating, then

(A) γ=3α

(B) γ>3α

(C) γ<3α

(D) γ=2α

26. The statement of which is not true about the order of a reaction is

(A) order cannot be obtained theoretically

(B) order may be fractional

(C) order is the sum of the power to the concentration terms of reactants in rate expression

(D) order is always integer

27. A car turns a corner on a slippery road at a constant speed of 12m/s. If the coefficient of friction between the road and wheels is 0.4, the minimum radius of the arc (in metres) in which the car turns is

(A) 72

(B) 36

(C) 18

(D) 9

28. Inorganic graphite is

(A) B₃N₃H₆

(B) (BN)₃

(C) SiC

(D) Fe(CO)₅

29. A Carnot engine working between temperatures 300K and 600 K has work output of 800J per cycle. The amount of heat energy drown from the high temperature source in each cycle is

(A) 800J

(B) 1600J

(C) 3200J

(D) 6400J

30. Which amongst the following is the best conductor of electricity?

(A) Filtered hot water

(B) Distilled water

(C) Filtered water at room temperature

(D) Saline water

31. To measure the equivalent conductance (⋀°) of NH₄OH at infinitely diluted solution by using Kohlrausch’s law needs the ⋀° value of

(A) NH₄NO₃, NaOH, NaNO₃

(B) NH₄Cl, NaOH, NaNO₃

(C) NH₄Cl, NaOH, KCl

(D) NH₄NO₃, KOH, NaCl

32. The breaking stress for a wire of radius r of a given material is FN/m². The breaking stress for a wire made of same material but of radius 2r is

(A) F

(B) F/2

(C) F/3

(D) F/4

33. A ring shaped piece of metal is heated. If it expands, then the size of the hole of the ring would

(A) expand

(B) contract

(C) expand or contract depending on the average radius of the ring

(D) expand or contract depending on the coefficient of expansion of material of the ring

34. The Q-factor (quality factor) of a series resonance circuit having the values of inductance L, capacitance C, resistance R and resonant frequency ω₀ is

(A)  ω₀L/R

(B)  ω₀C/R

(C)  ω₀LCR

(D)  ω₀R/L

35. Electromagnetic theory suggest that light consists of

(A) magnetic vector alone

(B) electric vector alone

(C) electric and magnetic vectors perpendicular to each other

(D) electric and magnetic vectors parallel to each other

36. Which one of the following is not a double salt?

(A) K₂SO₄.Al₂(SO₄)₃.24H₂O

(B) FeSO₄.(NH₄)₂SO₄.6H₂O

(C) K₂SO₄.Cr₂(SO₄)₃.24H₂O

(D) K₄[Fe(CN)₆]

37. The temperature of an ideal black body becomes half of its original temperature. The amount of radiation emitted by the body will reduce by a factor of

(A) 1/16

(B) 1/4

(C) ½

(D) Remains unchanged

38. Number of electrons required to balance the following reaction are:

NO₃⁻ + 4H⁺ + __?___ e → 2H₂O + NO

(A) 5

(B) 4

(C) 3

(D) 2

39. Among the following compounds which one has zero dipole moment?

(A) NH₃

(B) H₃O

(C) CCl₄

(D) HCl

40. The plot which corresponds well with Van’t Hoff’s equation for chemical equilibrium of an exothermic reaction is

(A) 

(B) 

(C) 

(D) 

41. Detergent soap is used for cleaning clothes because

(A) it decreases the surface tension of water solvent

(B) it increases the strength of the solution

(C) it attracts dirt.

(D) it changes the chemical property of the solution

42. When the path of a light ray changes from one medium to another, the physical property that remains unchanged is

(A) Velocity

(B) Wavelength

(C) Frequency

(D) Refractive index

43. Which of the following represents the correct order of electron affinity?

(A) Cl>Br>I>F

(B) Cl>F<Br<I

(C) F>Cl>Br>I

(D) Cl>F>Br>I

44. Which of the following pure amine molecules, no intermolecular hydrogen bonding exists/exist?

(A) 1° amine

(B) 2° amine

(C) 3° amine

(D) All of the above

45. The rate of aromatic electrophilic substitution reaction in which of the following compounds?

(A) Benzene

(B) Nitrobenzene

(C) Toluene

(D) m-dinitrobenzene

46. A ray of light passes through a equilateral prism in such a way that the angle of incidence is equal to the angle of emergence. If the angle of emergence is ¾th of the angle of the prism, the value of angle of deviation is

(A) 45°

(B) 39°

(C) 20°

(D) 30°

47. The reduction of ketone with LiAlH₄

(A) always gives a primary alcohol

(B) always gives a secondary alcohol

(C) always gives a carboxylic acid

(D) always gives an alkane

48. Acetamide reacts with Br₂/aq. NaOH to give

(A) Methyl amine

(B) Dimethyl amine

(C) Ethyl amine

(D) Acetyl bromide

49. Which of the following compounds show cis-trans isomers?

(A) 1-butene

(B) 2-butene

(C) Cyclopropane

(D) Acetone

50. Two spheres of equal masses but of radii r and 2r are allowed to fall through air. The ratio of their terminal velocities is

(A) 1 : 4

(B) 1 : 2

(C) 1 : 32

(D) 2 : 1

51. Tyndall effect is shown by colloidal solution due to

(A) Brownian motion

(B) scattering of light

(C) charge on the colloid particles

(D) very small size of the colloid particles

52. Which among the following heterocyclic compounds contains sulphur atom?

(A) Pyrrole

(B) Furan

(C) Thiophene

(D) Pyridine

53. The radioactive nucleus ¹³N₇ decays to ¹³C₆ by emission of

(A) Neutron

(B) Proton

(C) Electron

(D) Positron

54. Sucrose on hydrolysis gives the following two monosaccharides:

(A) D-glucose and D-fructose

(B) D-glucose and D-galactose

(C) D-galactose and D-fructose

(D) D-fructose and D-ribose

55. The half-life of Radium is 1600 years. After 6400 years, what fraction of a Radium sample would remain unchanged?

(A) ¼

(B) ½

(C) ¹/₈

(D) ¹/₁₆

56. Oxidation numbers of chlorine in Cl₂O, Cl₂ and ClO₃⁻ are respectively

(A) +1, -1, +5

(B) +1, 0, -1

(C) +1, 0, -1

(D) +1, 0, +5

57. IUPAC name of [Pt(NH₃)₃(Br)(NO₂)Cl]Cl

(A) Triamminechlorobromonitroplatinum (IV) chloride

(B) Triamminebromochloronitroplatinum (IV) chloride

(C) Bromochloronitrotriammineplatinum (IV) chloride

(D) Triamminenitrochlorobromoplatinum (IV) chloride

58. A light body and a heavy body have equal kinetic energies. Which one has greater linear momentum?

(A) The heavy body

(B) The light body

(C) Both have equal momentum

(D) Supplied data are insufficient

59. The back e.m.f. of a D.C. motor is maximum when

(A) the speed of the motor is still on increase

(B) the motor has just started moving

(C) the motor has picked up maximum speed

(D) the motor has just been switched off

60. Three 2Ω resistors are connected to form a triangle. The equivalent resistance between any two corners is

(A) 6Ω

(B) 2Ω

(C) ¾Ω

(D) ⁴/₃Ω