Which of the following phenomena are caused due to ‘atmospheric refraction’?
1. Flickering of objects seen through a turbulent stream of hot air rising above a fire.
2. The reddening of the sun at sunrise and the sunset.
3. The apparent flattening of the Sun’s disc at sunrise and sunset.
4. The Sun is visible to us about 2 minutes before the actual sunrise, and about 2 minutes after the actual sunset.
Select the correct answer using the code given below.
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With reference to Pisces – a category of animals, consider the following statements:
1. Their skin is covered with scales and it has mucus glands on their skin.
2. They are aquatic animals that obtain oxygen dissolved in water by using gills.
3. Unlike humans, they are cold-blooded and have only three chambers in their heart.
Which of the statement(s) given above is/are correct?
Which of the following statement(s) about Acquired Immuno Deficiency Syndrome (AIDS) is/are correct?
1. AIDS is a congenital disease caused by a retrovirus known as Human Immuno deficiency Virus (HIV).
2. AIDS is characterised by a progressive decrease in the number of T-lymphocytes in the body of the infected person.
Select the correct answer using the code given below.
The immune system is a complex network of cells known as immune cells that contains lymphocytes. In this context, consider the following statements:
1. Lymphocytes are red blood cells and one of the body's main types of immune cells.
2. Lymphocytes are made in the bone marrow and found in the blood and lymph tissue.
Which of the statements given above is/are correct?
Consider the following statements about ‘Biochemical Oxygen Demand’ (BOD):
1. It is the amount of oxygen required by bacteria to break down the organic matter present in a certain volume of a sample of water.
2. Highly polluted water have BOD value of less than 5 ppm.
Which of the statements given above is/are correct?
The ‘scattering of light’ is responsible for which of the following phenomena in nature?
1. Tyndall effect.
2. Colour of water in deep sea.
3. Blue colour of the sky.
4. Rainbow formation.
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Compass is an important tool used for navigation since old days. In this context, consider the following statements:
1. The compass needle is a magnet which align itself in a particular direction.
2. The compass needle always points towards the magnetic south pole of the earth.
Which of the statement(s) given above is/are correct?
When light enter the human eye, it passes through the different parts of the eye. In this context arrange the following in the correct sequence:
Which of the following diseases and their causative agents is NOT correctly matched?
Disease | Causative Agent |
1. Ringworms | Fungi |
2. Amoebiasis | Protozoan |
3. Plague | Bacterium |
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Which of the following phenomena are caused due to ‘atmospheric refraction’?
1. Flickering of objects seen through a turbulent stream of hot air rising above a fire.
2. The reddening of the sun at sunrise and the sunset.
3. The apparent flattening of the Sun’s disc at sunrise and sunset.
4. The Sun is visible to us about 2 minutes before the actual sunrise, and about 2 minutes after the actual sunset.
Select the correct answer using the code given below.
Some countries now use alcohol as an additive in petrol. In context of this, consider the following statements:
1. Addition of alcohol increases the burning efficiency of petrol and reduces knocking.
2. Petrol added with small quantities of alcohol becomes more stable and doesn’t become too hot in warm areas or too cold in freezing temperatures.
3. Alcohol is a cleaner fuel which gives rise to only carbon dioxide and water on burning in sufficient oxygen.
Which of the statements given above is the correct reason for using alcohol as an additive in petrol?