In the context of nature of light, read the following statements carefully:
1. Light does not travel in the same direction in all mediums.
2. Light propagates with different speeds in different mediums.
3. Light travels fastest in air with speed of 3×108 m/s.
4. Speed of light reduces considerably in glass or water.
Which of the statements given above is/are correct?
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Consider the following statements:
1. The motion of the moon around the earth is due to the centrifugal force.
2. The moon rotates around its axis due to the gravitational pull of the earth.
Which of the statement(s) given above is/are NOT correct?
Read the following statements carefully in the context of ‘particulate pollutants’?
1. Smoke particulates consist of gaseous or mixture of gaseous and liquid particles formed during combustion of organic matter.
2. Dust is composed of fine solid particles produced during crushing, grinding and attribution of solid materials.
3. Mists are produced by particles of spray liquids and by condensation of vapours in air.
4. Fumes are generally obtained by the condensation of vapours during sublimation, and boiling.
Which of the statements given above are correct?
Consider the following statements with reference to the ‘magnetic field’ of a bar magnet:
1. Magnetic field is a quantity that has both direction and magnitude.
2. Inside the magnet, the direction of field lines is from its south pole to north pole.
3. Magnetic field-lines of two different magnets can intersect each other.
Which of the statement(s) given above is/are correct?
Consider the following statements:
1.
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?
In the context of ‘immunity’ in human body, which of the following statements is/are correct?
1. Skin on our body is an example of innate immunity.
2. Acquired immunity is characterised by memory.
3. Injecting the microbes deliberately during immunisation induce passive immunity.
Select the correct answer using the code given below.
Consider the following statements:
1. Some substances like carbon dioxide or oxygen can move across the cell membrane by a process called Osmosis.
2. In the cell’s external environment, the concentration of carbon dioxide is low as compared to that inside the cell.
Which of the statement(s) given above is/are correct?
Consider the following statements:
1. Anti-viral medicines are harder to make as viruses have biochemical mechanisms of their own.
2. Anti-bacterial medicines target both bacteria and fungi.
Which of the statement(s) given above is/are correct?
Unicellular organism are unique because they are made up of a single cell only. Which of the following is/are examples of unicellular organisms?
1. Amoeba
2. Yeast
3. Bacteria
Select the correct answer using the code given below:
Which of the following statement(s) is/are correct?
1. The B-lymphocytes in human body produce an army of proteins in response to pathogens into our blood to fight with them.
2. The T-lymphocytes mediate cell-mediated immunity (CMI) which is responsible for the graft (transplanted body-part) rejection.
Select the correct answer using the code given below.