CHEMISTRYRATE OF CHEMICAL REACTIONS

Chemistry CBT – Rate of Chemical Reactions

Time: 30:00

CHEMISTRY LECTURERATE OF CHEMICAL REACTIONS

Chemistry CBT – Cells and Batteries

Time: 30:00

PHYSICS TEMPERATURECBT

PHYSICS CBT – TEMPERATURE & PRESSURE (1–40)

Time: 0 s

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Theory Questions (Click to View Answers)

1. Draw and label a liquid-in-glass thermometer.

Correction: Include scale markings, mercury/alcohol column, bulb, and tube.

2. A gas in a sealed container at 2 atm is heated from 300K to 450K. Calculate the new pressure.

Correction: P2 = P1×(T2/T1) = 2×(450/300) = 3 atm

3. A solid rod of length 1 m has α = 1.2×10⁻⁵ /°C. If heated by 50°C, find expansion.

Correction: ΔL = α×L×ΔT = 1.2×10⁻⁵ ×1×50 = 0.0006 m = 0.6 mm

4. Draw a thermocouple setup showing junction, metals, and voltage output.

Correction: Diagram: Metal A + Metal B junction → voltage measurement device → temperature proportional.

5. A gas at 1.5 atm is heated from 200K to 400K at constant volume. Find final pressure.

Correction: P2 = P1×(T2/T1) = 1.5 × (400/200) = 3 atm

PHYSICS LECTURE TEMPERATURE

PHYSICS LECTURE – TEMPERATURE AND RELATED CONCEPTS

1. Temperature

Temperature is a measure of the degree of hotness or coldness of a body. It is a physical quantity that determines the direction of heat transfer between bodies.

Illustration:
Temperature gradient: Hot body 🔥 → Cold body ❄

2. Measurement of Temperature

Temperature is measured using:

• Liquid-in-glass thermometer: Mercury or alcohol in a glass tube expands with heat.
• Thermocouple: Junction of two different metals generates voltage depending on temperature.
• Resistance thermometer: Resistance of wire changes with temperature.

Liquid-in-glass thermometer:
|
| Mercury/Alcohol rises with heat ↑
|___________

3. Temperature and Gas Pressure

The pressure of a gas is directly proportional to its absolute temperature if the volume is kept constant (Gay-Lussac’s law):

P ∝ T or P1/T1 = P2/T2

Pressure-Temperature relation:
Cylinder with piston: Heating → Gas molecules move faster → Pressure ↑

4. Pressure Laws

• Boyle’s Law: At constant temperature, P × V = constant
• Charles’ Law: At constant pressure, V ∝ T
• Gay-Lussac’s Law: At constant volume, P ∝ T

5. Thermometer and Thermocouple

• Thermometer measures temperature; liquid expands with heat.
• Thermocouple generates a voltage difference between two metals, giving temperature readings.

Thermocouple setup:
Metal A + Metal B → Junction → Voltage ∝ Temperature → Display

6. Molecular Expansion of Temperature

As temperature increases:

• Molecules vibrate faster.
• Solids expand (linear, area, volume expansion).
• Liquids expand (e.g., mercury in thermometers).
• Gases expand and pressure rises if volume is fixed.

Linear Expansion:
|---------| → |---------| (length increases)
Material expands with heat

7. Summary

• Temperature measures hotness/coldness.
• Thermometers and thermocouples are primary instruments.
• Pressure of gases rises with temperature (Pressure Law).
• Molecular expansion explains solids, liquids, gases behavior on heating.

BIOLOGY POLLUTIONCBT

BIOLOGY CBT – POLLUTION

Time: 0 s

POLLUTION → AIR | WATER | SOIL → Effects on Living Things

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Theory Questions (Click to Reveal Answers)

1. Define pollution and mention its major types.

Correction: Pollution is the introduction of harmful substances into the environment. Major types are air, water, and soil pollution.

2. Explain two effects of air pollution.

Correction: Air pollution causes respiratory diseases like asthma and bronchitis, and also leads to acid rain which damages crops and buildings.

3. Describe how water pollution affects aquatic life.

Correction: Pollutants such as oil and chemicals reduce oxygen levels, poison fish, and destroy aquatic ecosystems.

4. State three methods of controlling soil pollution.

Correction: Proper waste disposal, recycling plastics, and reducing use of chemical fertilizers and pesticides help control soil pollution.

5. Discuss the importance of pollution control.

Correction: Pollution control protects human health, preserves biodiversity, maintains soil fertility, ensures clean water supply, and prevents climate change.

BIOLOGY, POLLUTION

BIOLOGY LECTURE: POLLUTION

1. Meaning of Pollution

Pollution is the introduction of harmful substances (pollutants) into the environment in quantities that cause damage to living organisms and natural resources.

2. Types of Pollution

A. Atmospheric (Air) Pollution

Air pollution occurs when harmful gases, smoke, dust, and chemicals are released into the atmosphere.

FACTORIES → Smoke (CO₂, SO₂) ↓ ATMOSPHERE (Air Pollution) ↓ Humans & Plants Affected

Common Air Pollutants and Composition:

• Carbon monoxide (CO)
• Carbon dioxide (CO₂)
• Sulphur dioxide (SO₂)
• Nitrogen oxides (NOₓ)
• Chlorofluorocarbons (CFCs)
• Particulate matter (dust, smoke)

B. Water Pollution

Water pollution happens when harmful substances enter rivers, lakes, seas, and underground water.

INDUSTRY WASTE → RIVER → DEAD FISH ↑ OIL SPILL / SEWAGE

Water Pollutants:

• Oil spills
• Sewage
• Industrial chemicals
• Fertilizers (nitrates & phosphates)
• Heavy metals (lead, mercury)

C. Soil Pollution

Soil pollution occurs when harmful chemicals contaminate the land.

Pesticides / Chemicals ↓ SOIL ↓ Crops Contaminated

Soil Pollutants:

• Pesticides
• Herbicides
• Plastic waste
• Industrial waste
• Heavy metals

3. Side Effects of Pollution

Effects of Air Pollution:

• Respiratory diseases (asthma, bronchitis)
• Acid rain
• Global warming
• Ozone layer depletion

Effects of Water Pollution:

• Death of aquatic organisms
• Water-borne diseases (cholera, typhoid)
• Shortage of clean drinking water

Effects of Soil Pollution:

• Reduced soil fertility
• Contaminated crops
• Destruction of microorganisms

4. Control of Pollution

Control of Air Pollution:

• Use of clean energy (solar, wind)
• Planting trees (afforestation)
• Proper vehicle maintenance
• Installing filters in factories

Control of Water Pollution:

• Proper sewage treatment
• Avoid dumping waste in rivers
• Control of oil spills
• Industrial waste treatment

Control of Soil Pollution:

• Proper waste disposal
• Recycling plastics
• Reduced use of pesticides
• Organic farming methods

5. Summary Diagram

POLLUTION / | \ AIR WATER SOIL | | | Diseases Dead Fish Poor Crops

DANGERS OF TAKING DRUGS/ALCOHOL BEFORE HAVING SEX

Dangers of Drugs and Alcohol Before Sex

Introduction

Using drugs or alcohol before sexual activity may seem harmless to some, but it can have serious physical, emotional, and legal consequences. It impairs judgment, reduces consent clarity, and increases the risk of sexually transmitted infections (STIs) and unintended pregnancies.

Immediate Risks

• Impaired Judgment: Alcohol and drugs can reduce your ability to make safe decisions.
• Increased Risky Behavior: You may engage in unprotected sex or act impulsively.
• Reduced Physical Performance: Some substances can cause erectile dysfunction or difficulty achieving orgasm.
• Memory Blackouts: You may not remember sexual encounters, which could affect consent and personal safety.

Long-Term Risks

• Sexual Health: Higher chances of contracting STIs or HIV.
• Addiction: Using substances to enhance sexual experience can lead to dependency.
• Emotional Consequences: Feelings of guilt, regret, or trauma may follow.
• Legal Issues: Engaging in sexual activity while intoxicated may have legal ramifications, especially regarding consent.

Important Warning