1. Which of the following is an example of a communicable disease?
A) Cancer
B) Diabetes
C) COVID-19
D) Asthma
Answer: C) COVID-19.
2. Most electromagnets use which material as a core to make them stronger?
A) Aluminium
B) Copper
C) Iron
D) Plastic
Answer: C) Iron.
3. Gravitational force is always a ________ force.
A) Repulsive
B) Contact
C) Attractive
D) Static
Answer: C) Attractive.
4. Which practical unit is equal to 100 pascals (Pa) when measuring air pressure?
A) Newton
B) Millibar
C) Kilogram
D) Joule
Answer: B) Millibar.
5. In which state of matter are particles tightly packed and held in fixed positions?
A) Solid
B) Liquid
C) Gas
D) Plasma
Answer: A) Solid.
6. Why is nichrome wire used in heating elements of appliances?
A) It is very cheap
B) it offers higher resistance than copper
C) It is a perfect insulator
D) It is a magnetic material
Answer: B) It offers higher resistance than copper.
7. If an object weighs 10 N on Earth, what is its approximate weight on the Moon?
A) 10 N
B) 60 N
C) 1.6 N
D) 0 N
Answer: C) 1.6 N.
8. What tool is used to describe air quality based on the presence of pollutants?
A) BMI Index
B) Pressure Gauge
C) Air Quality Index (AQI)
D) Seismograph
Answer: C) Air Quality Index (AQI).
9. Who discovered the first vaccine (for smallpox) in the late 1700s?
A) Alexander Fleming
B) Edward Jenner
C) Alessandro Volta
D) Acharya Kanad
Answer: B) Edward Jenner.
10. Bronze is an alloy typically made of copper and which other metal?
A) Zinc
B) Iron
C) Tin
D) Gold
Answer: C) Tin.
Section B: Case Based Questions (2 x 4 = 8 Marks)
Case 1: In Bhadrak district, Odisha, a community-led sanitation campaign helped more people build and use toilets, significantly reducing open defecation.
Q) What impact did this campaign have on child health and what can we infer?
The campaign improved child health by causing fewer cases of diarrhoea and infections. We can infer that simple steps like good sanitation greatly reduce the spread of communicable diseases.
Case 2: Scientists are developing lithium-ion and solid-state batteries as portable sources of electricity for devices and vehicles.
Q) Why is recycling used batteries important for the planet?
Batteries contain harmful materials like acids and metals (lead, lithium) that can cause fires or damage the environment if thrown in regular garbage. Recycling also recovers valuable materials to be reused.
Section C: Match the Following (4 x 1 = 4 Marks)
Match Column A (Device) with Column B (Effect):
1. Electromagnet a) Chemical reactions to produce electricity
2. Electric Iron b) Uses magnetic effect of current
3. Voltaic Cell c) High resistance generates heat
4. Nichrome Wire d) Uses heating effect of current
1-b, 2-d, 3-a, 4-c.
Section D: Short Answer Questions (5 x 2 = 10 Marks)
1. Why does a rubber sucker stick to a smooth flat surface?
Pressing the sucker pushes air out, and the higher external atmospheric pressure pushes it firmly against the surface. This creates a pressure difference that keeps it stuck.
2. What is buoyant force (upthrust)?
Buoyant force is the upward force exerted by a liquid on an object placed in it. It acts in the opposite direction to gravity.
3. Why are interparticle forces strongest in solids?
Particles in solids are very close together, and since interparticle force increases as distance decreases, the attraction is maximum. This packing prevents particles from moving past one another.
4. Give two examples of common alloys.
Common alloys include stainless steel, which is used in construction and utensils, and brass, which is a mixture of copper and zinc.
5. What is the difference between a symptom and a sign of being unwell?
A symptom is what a person feels (like pain), while a sign is something that can be seen or measured by a doctor (like a rash or fever).
Section E: Long Answer Questions (2 x 4 = 8 Marks)
1. Explain the process of formation of a thunderstorm and lightning.
Strong upward and downward winds cause rubbing between water droplets and ice particles, creating static electric charges within clouds. Positively charged ice particles move to the upper cloud, while negative droplets stay lower, causing the ground below to become positively charged. When the buildup of charges becomes large enough to break air's insulation, a sudden flow of charges occurs, creating a bright flash called lightning. This heats the air rapidly, producing the loud sound we know as thunder.
2. How can the strength of an electromagnet be increased? Mention three factors.
The strength of an electromagnet can be increased by using a battery with more cells to provide a larger electric current. Another method is to increase the total number of turns of the insulated wire in the coil. Inserting an iron core inside the coil also makes the electromagnet significantly stronger. Changing either the current magnitude or the coil turns directly alters the strength of the magnetic field produced.
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