General Science - MCQ Practice Questions

The Weber (Wb) is the SI unit of magnetic flux, defined as Tesla × meter². 1 Wb = 1 T·m².

Using transformer equation: Vₛ/Vₚ = Nₛ/Nₚ. Vₛ = 220 × ($\frac{500}{100}$) = 220 × 5 = 1100 V.

An alpha particle is a helium-4 nucleus (₂He⁴) with 2 protons and 2 neutrons. Alpha decay decreases atomic number by 2 and mass number by 4. Alpha particles have low penetration power.

In beta-minus decay, a neutron converts to a proton, emitting an electron (beta particle) and an antineutrino. This increases atomic number by 1.

Rayleigh scattering causes shorter blue wavelengths to scatter more effectively than longer red wavelengths when sunlight passes through the atmosphere, making the sky appear blue.

Using P = V²/R, we get R = V²/P = (250)²/1000 = $\frac{62500}{1000}$ = 62.5 Ω.

When object distance (5 cm) < focal length (10 cm), the object is between the mirror and focus. A concave mirror forms a virtual, erect, and magnified image in this case.

For parallel resistances: 1/R = 1/R₁ + 1/R₂ = $\frac{1}{10}$ + $\frac{1}{20}$ = $\frac{3}{20}$. Therefore R = $\frac{20}{3}$ = 6.67 Ω.

Using v = fλ, where v = 330 m/s and f = 440 Hz. λ = v/f = $\frac{330}{440}$ = 0.75 m.

Elastic potential energy E = ($\frac{1}{2}$)kx². 5 = ($\frac{1}{2}$)k(0.1)². 5 = 0.005k. k = 1000 N/m.

The photoelectric effect occurs when light of frequency greater than or equal to the threshold frequency strikes a metal surface, causing electron emission. It demonstrates the particle nature of light.

Kinetic energy KE = ($\frac{1}{2}$)mv². When velocity is doubled: KE' = ($\frac{1}{2}$)m(2v)² = ($\frac{1}{2}$)m(4v²) = 4 × ($\frac{1}{2}$)mv² = 4K.

The Second Law of Thermodynamics states that entropy of an isolated system increases or remains constant. Heat spontaneously flows from hot to cold, not vice versa, establishing the direction of processes.

At maximum height, v = 0. Using v² = u² - 2gh: 0 = 20² - 2(10)h. 20h = 400. h = 20 m.

For capacitors in series: 1/C = 1/C₁ + 1/C₂ = $\frac{1}{2}$ + $\frac{1}{3}$ = $\frac{5}{6}$. Therefore C = $\frac{6}{5}$ = 1.2 μF.

Centripetal acceleration a = v²/r = (10)²/5 = $\frac{100}{5}$ = 20 m/s².

Understanding:

We need to identify the disease caused by Vitamin C deficiency.

Step 1: Matching vitamins to deficiency diseases

Each vitamin deficiency leads to a specific disease:

Step 2: Identifying Scurvy

Scurvy is caused by a lack of Vitamin C (ascorbic acid). It is characterized by swollen and bleeding gums, weakness, anaemia, and skin haemorrhages. Vitamin C is essential for collagen synthesis, which maintains the integrity of blood vessels and connective tissue.

Answer:

The disease caused by Vitamin C deficiency is Scurvy.

Quick Tip:

A helpful mnemonic — 'C for Citrus, C for Scurvy': sailors historically suffered from scurvy due to lack of fresh fruits during long voyages.

Understanding:

We need to identify the microorganism responsible for causing Tuberculosis.

Step 1: Identifying the causative agents of common diseases

Step 2: About Mycobacterium tuberculosis

Tuberculosis is a highly contagious airborne disease primarily affecting the lungs. It is caused by the bacterium Mycobacterium tuberculosis, discovered by Robert Koch in 1882. It spreads through respiratory droplets when an infected person coughs or sneezes.

Answer:

The causative agent of Tuberculosis is Mycobacterium tuberculosis.

Quick Tip:

Robert Koch discovered M. tuberculosis on 24 March 1882 — this date is now celebrated as World Tuberculosis Day.

Understanding:

We need to identify the organ affected by Cirrhosis.

Step 1: Understanding Cirrhosis

Cirrhosis is a chronic liver disease in which normal liver tissue is replaced by scar tissue (fibrosis), severely impairing liver function. Common causes include chronic alcoholism, hepatitis B and C infections, and non-alcoholic fatty liver disease.

Step 2: Ruling out other options

None of these are associated with Cirrhosis.

Answer:

Cirrhosis is a disease that affects the Liver.

Quick Tip:

Cirrhosis is an irreversible condition — the scarred liver tissue cannot regenerate, making early diagnosis and lifestyle changes critical.

Understanding:

We need to identify the mosquito species that transmits Dengue fever.

Step 1: Mapping mosquito species to diseases

Step 2: About Dengue transmission

Dengue is a viral disease caused by the Dengue virus (DENV), which belongs to the Flavivirus genus. It is spread primarily by the female Aedes aegypti mosquito, which typically bites during the day. Dengue is characterised by high fever, severe headache, pain behind the eyes, joint and muscle pain, and rash.

Answer:

Dengue is transmitted by the Aedes aegypti mosquito.

Quick Tip:

Aedes aegypti mosquitoes breed in stagnant, clean water stored in containers, flower pots, and tyres — eliminating such breeding sites is the primary prevention strategy.