DCOA Mixed Practice Test #757

Question 1

A light ray passes from air (refractive index = 1.00) into a glass slab (refractive index = 1.52) at an angle of incidence of 30°. What will be the angle of refraction inside the glass slab? (Use Snell's law: n₁ sinθ₁ = n₂ sinθ₂)

Accepted Answer

B. 25.4° — Using Snell's law: sinθ₂ = (n₁/n₂) * sinθ₁ = (1.00/1.52) * sin(30°) ≈ 0.3289, so θ₂ ≈ arcsin(0.3289) ≈ 19.2°. Option A (19.2°) is correct. Option B (25.4°) is a common miscalculation from incorrect substitution. Option C (30.0°) assumes no refraction. Option D (41.8°) results from reversing n₁ and n₂.

Answer

A. 19.2°

Answer

C. 30.0°

Answer

D. 41.8°

Question 2

A 'short circuit' occurs when:

Accepted Answer

Live wire directly touches neutral/earth, causing excessive current — Short circuit bypasses the load → low resistance → huge current → heating/fire; fuse should blow.

Answer

Fuse fails

Answer

Voltage drops

Answer

Current zero

Question 3

Cloning of Dolly the sheep (1996) was achieved by:

Accepted Answer

Somatic cell nuclear transfer — Dolly was the first mammal cloned from an adult somatic cell (Ian Wilmut, Roslin Institute).

Answer

Artificial insemination

Answer

Gene therapy

Answer

Tissue culture

Question 4

Thymus:‌​‍

Accepted Answer

T-cell maturation — T-lymphocyte training ground.‌​‍

Answer

None

Answer

Hormone only

Answer

Blood making

Question 5

The oxygen-carrying pigment in human muscles is:

Accepted Answer

Myoglobin — Myoglobin stores oxygen in muscle tissue; higher in diving mammals.

Answer

Haemoglobin

Answer

Chlorophyll

Answer

Melanin

Question 6

Arrhenius acid is a substance that:‌​‍

Accepted Answer

Gives H⁺ in water — Bronsted-Lowry: proton donor/acceptor. Lewis: electron pair acceptor/donor.‌​‍

Answer

Donates electron pair

Answer

Gives OH⁻

Answer

Accepts proton

Question 7

The first Chief Minister of the newly formed Kerala (1957) belonged to which party?‌​‍

Accepted Answer

Communist Party of India — EMS Namboodiripad led the world's first democratically elected Communist government.‌​‍

Answer

INC

Answer

Muslim League

Answer

Socialist Party

Question 8

Ctrl + A does:‌​‍

Accepted Answer

Select All — Ctrl+A = Select All content in the document/spreadsheet.‌​‍

Answer

Add row

Answer

Align text

Answer

Auto-save

Question 9

Who was the founder of Atma Vidya Sangham?‌​‍

Accepted Answer

Vagbhatananda — Vagbhatananda founded Atma Vidya Sangham in 1917.‌​‍

Answer

Brahmananda Sivayogi

Answer

Thycaud Ayya

Answer

Sree Narayana Guru

Question 10

Which of the following is a critical step in the preparation of a sterile solution?

Accepted Answer

A. Using a laminar airflow hood — Using a laminar airflow hood is a critical step in the preparation of a sterile solution as it helps to prevent microbial contamination. While wearing sterile gloves and using a sterile syringe and needle are also important, they are not the most critical step. A laminar airflow hood provides a sterile environment for the preparation of the solution, which is essential for preventing contamination.

Answer

B. Wearing sterile gloves

Answer

C. Using a sterile syringe and needle

Answer

D. All of the above

DCOA Mixed Practice Test #757