CUET UG 2021 previous year paper practice · PYQ-pattern set

CUET UG 2021 PYQ-pattern questions

Showing 10 of the 18 PYQ-pattern questions in this set — freshly worded in that year's pattern, not the original questions. Answers and solutions open under each question.

1. Q1 · Science & Technology

   What is the chemical formula of common salt (sodium chloride)?

   • A. NaCl2
   • B. NaCl
   • C. Na2Cl
   • D. NaClO
   Answer and solution

   Answer: B

   Common salt is sodium chloride with the chemical formula NaCl, formed by the ionic bonding of sodium (Na+) and chloride (Cl-) ions.

2. Q2 · Numerical Ability

   The simple interest on a sum of money at 8% per annum for 3 years is ₹960. What is the principal amount?

   • A. ₹3,500
   • B. ₹4,000
   • C. ₹4,200
   • D. ₹4,800
   Answer and solution

   Answer: B

   Simple Interest = (P × R × T)/100. So 960 = (P × 8 × 3)/100, which gives P = (960 × 100)/(8 × 3) = ₹4,000.

3. Q3 · Logical & Analytical Reasoning

   P, Q, R, S, and T are sitting in a row. P is between Q and S. T is not at the start of the row. R is at one of the ends. If Q is next to R, what is the arrangement from left to right?

   • A. R Q P S T
   • B. T Q P S R
   • C. R P Q S T
   • D. Q R P S T
   Answer and solution

   Answer: A

   R is at one end and Q is next to R. P is between Q and S, and T is not at the start, so arrangement is R Q P S T.

4. Q4 · Differential Equations

   The order and degree of the differential equation d²y/dx² + 3(dy/dx)² = x²log(d²y/dx²) are:

   • A. Order 2, degree 1
   • B. Order 2, degree 2
   • C. Order 2, degree not defined
   • D. Order 1, degree 2
   Answer and solution

   Answer: C

   The order is 2 as the highest derivative is d²y/dx². The degree is not defined because the differential equation contains log(d²y/dx²), making it transcendental in the derivative.

5. Q5 · Electromagnetic Induction & Alternating Current

   A rectangular coil of 50 turns, each of area 0.1 m², is rotated at 60 revolutions per second in a uniform magnetic field of 0.04 T about an axis perpendicular to the field. What is the maximum emf induced in the coil?

   • A. 75.4 V
   • B. 150.8 V
   • C. 37.7 V
   • D. 188.5 V
   Answer and solution

   Answer: A

   Maximum emf ε₀ = NABω = 50 × 0.1 × 0.04 × 2π × 60 = 0.2 × 2π × 60 = 24π ≈ 75.4 V.

6. Q6 · Optics

   A ray of light passes from air into glass with refractive index 1.5. If the angle of incidence is 60°, what is the angle of refraction? (sin 60° = 0.866, sin 35.3° ≈ 0.577)

   • A. 35.3°
   • B. 40°
   • C. 30°
   • D. 45°
   Answer and solution

   Answer: A

   Using Snell's law: n₁sin(i) = n₂sin(r). So 1 × sin(60°) = 1.5 × sin(r), giving sin(r) = 0.866/1.5 = 0.577, hence r ≈ 35.3°.

7. Q7 · Communication Systems

   The frequency range suitable for ground wave propagation in long-distance communication is approximately:

   • A. 100 MHz - 200 MHz
   • B. 10 MHz - 30 MHz
   • C. 500 kHz - 1500 kHz
   • D. 3 GHz - 30 GHz
   Answer and solution

   Answer: C

   Ground wave propagation is effective for frequencies up to about 2 MHz. The AM broadcast band (500 kHz - 1500 kHz) uses ground wave propagation for medium-distance communication.

8. Q8 · Surface Chemistry

   Which of the following statements about physical and chemical adsorption is INCORRECT?

   • A. Physical adsorption is reversible while chemical adsorption may be irreversible
   • B. Enthalpy of physical adsorption is low (20-40 kJ/mol) compared to chemical adsorption (80-400 kJ/mol)
   • C. Physical adsorption involves multi-layer formation while chemical adsorption is usually monolayer
   • D. Physical adsorption increases with increase in temperature while chemical adsorption decreases
   Answer and solution

   Answer: D

   Physical adsorption is exothermic and decreases with increasing temperature. Chemical adsorption initially increases with temperature (due to activation energy requirement) then decreases. Statement D is incorrect.

9. Q9 · Haloalkanes & Haloarenes

   Which of the following compounds will undergo nucleophilic substitution reaction most readily?

   • A. Chlorobenzene
   • B. 2-Chloro-2-methylpropane
   • C. 1-Chlorobutane
   • D. Chloroethane
   Answer and solution

   Answer: B

   2-Chloro-2-methylpropane is a tertiary alkyl halide which undergoes SN1 mechanism most readily due to formation of stable tertiary carbocation.

10. Q10 · Coordination Compounds

    The spin-only magnetic moment value for the complex [Co(NH₃)₆]³⁺ is:

    • A. 0 BM
    • B. 2.83 BM
    • C. 4.90 BM
    • D. 3.87 BM
    Answer and solution

    Answer: A

    Co³⁺ has d⁶ configuration. NH₃ is a strong field ligand causing pairing of all electrons (t₂g⁶), resulting in zero unpaired electrons and magnetic moment = 0 BM.