Explanation

Question:

 What are antioxidants and why are they used in foods? Write a short note on natural and synthetic antioxidants. (5 amrks)

Antioxidants:
Antioxidants are compounds that prevent oxidative damage in cells, thus extending the shelf life and quality of foods.

Natural vs. Synthetic:
Natural antioxidants (e.g., vitamin C, E) are derived from plants, while synthetic ones (e.g., BHA, BHT) are lab-made; both help preserve food freshness but vary in sources and stability.

Explanation

Question: A telephone company charges initially Rs.0.50 and then Rs. 0.11 for every minute. Write an expression that gives the cost of a call that lasts N minutes. (5 marks)

I apple - 2 Rs

8 apples = 2x8

= 16 Rs

Initial charges = Rs 0.5-

Next every min charge = RS0.11 Rs 

No. minutes charges = Nx0.1 =0.11N.R

Total charge = (0.50 +0.11N) Rs

Explanation

Total number of cards: 12

(i) Probability of drawing '8'

• Favorable outcomes: 1 (card number 8)
• Probability: 1/12

(ii) Probability of drawing an even number

• Favorable outcomes: 6 (2, 4, 6, 8, 10, 12)
• Probability: 6/12 = 1/2

(iii) Probability of drawing a perfect square

• Favorable outcomes: 4 (1, 4, 9)
• Probability: 4/12 = 1/3

(iv) Probability of drawing a negative number

• Favorable outcomes: 0 (no negative numbers)
• Probability: 0/12 = 0

(v) Probability of drawing a number less than 13

• Favorable outcomes: 12 (all cards are less than 13)
• Probability: 12/12 = 1

In summary:

• Probability of drawing '8': 1/12
• Probability of drawing an even number: 1/2
• Probability of drawing a perfect square: 1/3
• Probability of drawing a negative number: 0
• Probability of drawing a number less than 13: 1

Explanation

Explanation

The scintillation nuclear radiation detector detects the alpha rays per second. When the energy of the alpha rays (Eα) in MeV increases, the number of counts (Nc) on the detector also increases linearly as shown in the table below. 

Draw the graph of Nc as a function of Eα (MeV) and find the energy of the unknown alpha ray if the number of counts is 31600.

Explanation

The perimeter of the rectangle given below is 114 cm. Find the area of the rectangle. (5 marks)

Explanation

Seismograph: an instrument used to detect and record earthquakes.

Explanation

Computer memory is of two basic types.

Primary memory(RAM and ROM) and Secondary memory(hard drive,CD,etc.

Explanation

NOTE: The question has 4 parts each part of the question contains 5 marks

Question: (a) What is the difference between fog and smog? What are the causes of smog and its effects on human health? Write a short note on one of the latest technologies to eliminate smog and avoid atmospheric pollution. (5)

Difference between Fog and Smog:
Fog is a natural weather phenomenon caused by condensed water vapor, while smog is a type of air pollution formed from pollutants, mainly from vehicles and industry.

Causes of Smog:
Smog is caused by emissions from vehicles, factories,

Effects on Human Health:
Smog can cause respiratory issues, eye irritation

Latest Technology to Eliminate Smog:
Photocatalytic materials, such as titanium dioxide coatings

*

(b)What is the role of oxygen-demanding wastes in water pollution? How it can be prevented? (5)

Role in Water Pollution:
Oxygen-demanding wastes, like organic matter from sewage, agricultural runoff, and industrial discharge, consume oxygen in water as they decompose.

Reducing pollution sources by treating wastewater, promoting sustainable agriculture

*

(c)What is the biosphere? Write a note on the ‘Energy Resources’ available in the biosphere. (5)

The biosphere is the global ecological system that includes all living organisms and their interactions with the Earth's atmosphere, land, and water. Energy resources in the biosphere include solar energy, wind, water, and biomass, which are vital for sustaining life and ecosystems.

*

(d)What are the different layers of the atmosphere? On what basis these layers are classified? In which layer ‘Auroras’ are formed and where do satellites orbit? (5)

The atmosphere consists of five layers: the troposphere, stratosphere, mesosphere, thermosphere, and exosphere, classified based on temperature gradients and altitude.

Auroras form in the thermosphere, while satellites typically orbit in the exosphere.

Explanation

More details about this question will be shared soon