IAT 2025 Question Paper

IAT Mock Test 2026 – Part 1

Marking Scheme: +4 Correct | -1 Incorrect | 0 Unattempted

Q1. A particle moves in a straight line such that its displacement is given by x = t³ − 6t² + 9t + 4. At what time is its velocity zero?

(A) 1 s

(B) 2 s

(C) 3 s

(D) Both A and C

Correct Answer: (D)

v = dx/dt = 3t² − 12t + 9 = 3(t−1)(t−3). Therefore velocity is zero at t = 1 s and 3 s.

Q2. The number of stereoisomers possible for a compound with two chiral centers is:

(A) 2

(B) 4

(C) 6

(D) 8

Correct Answer: (B)

Maximum stereoisomers = 2ⁿ, where n = number of chiral centers. Hence 2² = 4.

Q3. If z = 1 + i√3, then the principal argument of z is:

(A) π/6

(B) π/3

(C) π/2

(D) 2π/3

Correct Answer: (B)

tan θ = √3/1 = √3, first quadrant ⇒ θ = π/3.

Q4. A wire of resistance R is stretched to double its original length. The new resistance becomes:

(A) R/2

(B) R

(C) 2R

(D) 4R

Correct Answer: (D)

On stretching to double length, area becomes half. R ∝ L/A ⇒ R' = (2L)/(A/2) = 4R.

Q5. Which species has maximum bond angle?

(A) NH₃

(B) H₂O

(C) CH₄

(D) BF₃

Correct Answer: (D)

BF₃ is trigonal planar with 120° bond angle, maximum among given options.