JEE Main Practice Set 10

90 Questions 300 Marks 180 Minutes +4 per correct answer
Time Remaining: 15:00

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?? Disclaimer: This is a practice paper with simulated questions based on the exam pattern. Not affiliated with the official examination body.
Sections: PhysicsChemistryMathematics
Q1. [+4, -1] Mathematics
⚠ Negative Marking: -1 mark for each wrong MCQ (no negative for Numerical Answer questions)
The sum of first n odd natural numbers is:
A. n
B. 2n
C. n^2
D. n(n+1)/2
Correct Answer: C
1 + 3 + 5 + ... + (2n-1) = n^2.
Q2. [+4, -1] Physics
A Carnot engine operates between two reservoirs at temperatures 500 K and 300 K. What is the efficiency of the engine?
A. 0.2
B. 0.4
C. 0.6
D. 0.8
Correct Answer: B
The efficiency of a Carnot engine is given by the equation eta = 1 - (T2/T1), where T1 and T2 are the temperatures of the two reservoirs. For the given temperatures, eta = 1 - (300/500) = 1 - 0.6 = 0.4.
Q3. [+4, -1] Chemistry
What is the IUPAC name of the compound with the formula CH3CH2CH2OH?
A. Propan-1-ol
B. Propan-2-ol
C. Butan-1-ol
D. Butan-2-ol
Correct Answer: A
The IUPAC name of the compound with the formula CH3CH2CH2OH is Propan-1-ol.
Q4. [+4, -1] Chemistry
What is the molecular formula of the compound with the empirical formula CH2O and a molecular weight of 120 g/mol?
A. C2H4O2
B. C3H6O3
C. C4H8O4
D. C5H10O5
Correct Answer: B
The empirical formula is CH2O, and its molecular weight is 30 g/mol. To find the molecular formula, we need to multiply the empirical formula by a factor that will give us the molecular weight of 120 g/mol. The factor is 120 / 30 = 4. So, the molecular formula is (CH2O) * 4 = C4H8O4 * (3/4) = C3H6O3.
Q5. [+4, -1] Mathematics
If the equation x^2 + 2x + 1 = 0 has two equal roots, what is the value of the discriminant?
A. 0
B. 1
C. 2
D. 4
Correct Answer: A
The discriminant of a quadratic equation ax^2 + bx + c = 0 is given by b^2 - 4ac. For the given equation x^2 + 2x + 1 = 0, a = 1, b = 2, and c = 1. The discriminant is 2^2 - 4*1*1 = 0.
Q6. [+4, -1] Chemistry
The gas used in welding is:
A. Methane
B. Ethane
C. Acetylene
D. Propane
Correct Answer: C
Acetylene (CH) produces high temperature flame used in oxy-acetylene welding.
Q7. [+4, -1] Mathematics
The value of x^2 dx is:
A. 0
B. 1/2
C. 1/3
D. 1
Correct Answer: C
x^2 dx = [x/3] = 1/3 - 0 = 1/3.
Q8. [+4, -1] Physics
The momentum of a photon of energy E is:
A. E/c^2
B. E/c
C. Ec
D. hE/c
Correct Answer: B
p = E/c for a photon (since E = pc).
Q9. [+4, -1] Chemistry
Which of these is NOT a greenhouse gas?
A. CO
B. CH
C. O
D. HO vapor
Correct Answer: C
Oxygen (O) is not a greenhouse gas. CO, CH, and HO vapor are GHGs.
Q10. [+4, -1] Physics
A block of mass 5 kg is moving with a velocity of 2 m/s. What is the magnitude of its momentum?
A. 5 kg m/s
B. 10 kg m/s
C. 15 kg m/s
D. 20 kg m/s
Correct Answer: B
The momentum of an object is given by the product of its mass and velocity. So, the magnitude of the momentum is p = mv = 5 kg * 2 m/s = 10 kg m/s.
Q11. [+4, -1] Mathematics
The number of ways to arrange letters of word CAT is:
A. 3
B. 4
C. 6
D. 9
Correct Answer: C
3! = 6 ways (CAT, CTA, ACT, ATC, TCA, TAC).
Q12. [+4, -1] Mathematics
If the function f(x) = x^3 - 2x^2 - 5x + 1 is given, what is the value of f(-1)?
A. 1
B. 3
C. 5
D. 7
Correct Answer: D
To find the value of f(-1), we substitute x = -1 into the function: f(-1) = (-1)^3 - 2(-1)^2 - 5(-1) + 1 = -1 - 2 + 5 + 1 = 3.
Q13. [+4, -1] Mathematics
The area of a circle with radius 7 cm is:
A. 144 cm^2
B. 154 cm^2
C. 154 cm^2
D. 44 cm^2
Correct Answer: C
A = pir^2 = (22/7) x 49 = 154 cm^2.
Q14. [+4, -1] Physics
An electron in the ground state of a hydrogen atom has an energy of -13.6 eV. What is the energy of the electron in the first excited state?
A. -3.4 eV
B. -6.8 eV
C. -10.2 eV
D. -13.6 eV
Correct Answer: A
The energy of the electron in the nth state of a hydrogen atom is given by En = -13.6 eV / n^2. For the first excited state, n = 2. So, E2 = -13.6 eV / 2^2 = -13.6 eV / 4 = -3.4 eV.
Q15. [+4, -1] Chemistry
Which of these is a noble gas?
A. Cl
B. N
C. Xenon
D. O
Correct Answer: C
Xenon (Xe) is a noble gas. Cl, N, O are diatomic gases.