NEET UG Practice Set 10

200 Questions 720 Marks 180 Minutes +4 per correct answer

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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: PhysicsChemistryBiology

Q1. [+4, -1] Biology

⚠ Negative Marking: -1 mark per wrong answer (+4 for correct, -1 for incorrect)

Which hormone is called the "fight or flight" hormone?

A. Insulin

B. Adrenaline

C. Thyroxine

D. Estrogen

Correct Answer: B
Adrenaline (epinephrine) prepares body for stress (increases HR, BP, etc.).

Q2. [+4, -1] Chemistry

The process of electrolysis is based on:

A. Chemical effect of current

B. Magnetic effect of current

C. Redox reactions

D. Heating effect

Correct Answer: C
Electrolysis involves redox reactions at electrodes driven by electric current.

Q3. [+4, -1] Physics

A wire of length L and area A has resistance R. If length is halved and area doubled, new resistance is:

A. R/2

B. R/4

C. R

D. 2R

Correct Answer: B
R' = (L/2)/(2A) = (L/A)/4 = R/4.

Q4. [+4, -1] Biology

The number of chromosomes in human cells is:

A. 23

B. 46

C. 48

D. 44

Correct Answer: B
Humans have 23 pairs = 46 chromosomes (22 autosomes + 1 sex chromosome pair).

Q5. [+4, -1] Chemistry

Which of the following reagents can be used to distinguish between propanal and propanone?

A. Tollen's reagent

B. Fehling's solution

C. Benedict's solution

D. All of the above

Correct Answer: D
Propanal is an aldehyde (CHCHCHO), and propanone is a ketone (CHCOCH). Aldehydes are generally more easily oxidized than ketones. They can reduce mild oxidizing agents, while ketones typically cannot (except under harsh conditions or specific structural features like alpha-hydroxy ketones). 1. **Tollen's reagent (ammoniacal silver nitrate):** Aldehydes reduce Tollen's reagent to metallic silver, forming a 'silver mirror' on the test tube. Ketones do not react. 2. **Fehling's solution (alkaline solution of copper(II) sulfate complexed with tartrate):** Aldehydes reduce the blue Cu^2 ions to red precipitate of cuprous oxide (CuO). Ketones do not react. 3. **Benedict's solution (alkaline solution of copper(II) sulfate complexed with citrate):** Similar to Fehling's solution, aldehydes reduce the blue Cu^2 ions to red precipitate of cuprous oxide. Ketones do not react. Since propanal (an aldehyde) will give a positive test with all three reagents, while propanone (a ketone) will not, all of them can be used to distinguish between the two compounds.

Q6. [+4, -1] Physics

A convex mirror always forms which type of image?

A. Real and inverted

B. Virtual and erect

C. Real and erect

D. Virtual and inverted

Correct Answer: B
Convex mirrors always form virtual, erect, and diminished images regardless of object position.

Q7. [+4, -1] Physics

What is the phenomenon where the frequency of a wave appears to change when the source and observer are moving relative to each other?

A. Diffraction

B. Refraction

C. Interference

D. Doppler effect

Correct Answer: D
The Doppler effect is the phenomenon where the frequency of a wave appears to change when the source and observer are moving relative to each other. This effect is commonly observed in sound waves and light waves.

Q8. [+4, -1] Biology

The universal donor blood group is:

A. A

B. B

C. AB

D. O

Correct Answer: D
O negative is universal donor (no A/B antigens, no Rh factor).

Q9. [+4, -1] Chemistry

The oxide that turns red litmus blue is:

A. CO

B. SO

C. NaO

D. PO

Correct Answer: C
NaO is basic oxide -> turns red litmus blue. CO, SO, PO are acidic.

Q10. [+4, -1] Chemistry

The shape of NH molecule is:

A. Trigonal planar

B. Trigonal pyramidal

C. Tetrahedral

D. Linear

Correct Answer: B
NH: 3 bond pairs + 1 lone pair -> trigonal pyramidal shape.

Q11. [+4, -1] Chemistry

What is the hybridization of the carbon atom in methane?

A. sp

B. sp2

C. sp3

D. sp3d

Correct Answer: C
The carbon atom in methane is bonded to four hydrogen atoms, and its electronic configuration is 1s2 2s2 2p2. To form four equivalent bonds, the carbon atom undergoes sp3 hybridization.

Q12. [+4, -1] Biology

The process of DNA replication is described as semi-conservative. What does this imply?

A. Each new DNA molecule consists of two entirely new strands.

B. Each new DNA molecule consists of one original strand and one newly synthesized strand.

C. The DNA molecule breaks down completely and reforms into new strands.

D. The replication process is only about 50% efficient.

Correct Answer: B
Semi-conservative replication means that each daughter DNA molecule contains one strand from the parent molecule and one newly synthesized strand.

Q13. [+4, -1] Physics

A convex lens has a focal length of 20 cm. An object is placed at a distance of 30 cm from the lens. What is the nature and position of the image formed?

A. Real, inverted, 60 cm from the lens on the opposite side.

B. Virtual, erect, 60 cm from the lens on the same side.

C. Real, inverted, 30 cm from the lens on the opposite side.

D. Virtual, erect, 30 cm from the lens on the same side.

Correct Answer: A
Using the lens formula 1/f = 1/v - 1/u, where f = 20 cm and u = -30 cm (object distance is negative). 1/20 = 1/v - 1/(-30) => 1/v = 1/20 - 1/30 = (3-2)/60 = 1/60. So, v = 60 cm. Since v is positive, the image is real and formed on the opposite side. The magnification m = v/u = 60/(-30) = -2, indicating an inverted image.

Q14. [+4, -1] Biology

The respiratory pigment in human blood is:

A. Chlorophyll

B. Hemoglobin

C. Melanin

D. Myoglobin

Correct Answer: B
Hemoglobin in RBCs transports O from lungs to tissues.

Q15. [+4, -1] Biology

Which hormone regulates blood sugar level?

A. Thyroxine

B. Insulin

C. Adrenaline

D. Estrogen

Correct Answer: B
Insulin lowers blood glucose, while glucagon raises it.