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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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?
Weeds are unwanted plants in a cultivated field. In this context, consider the following statements:
1. The weeds compete for food, space and light.
2. Weeds are responsible for affecting the growth of the crop.
3. Timely sowing of crops and crop rotation help in weed control.
Which of the statement(s) 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.
Select the correct answer using the code given below.
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?
Fertilizers are commercially produced plant nutrients. In this context, consider the following statements:
1. Fertilizers get washed away due to excessive irrigation.
2. Micro-organisms in the soil are harmed by the continuous use of fertilizers.
3. Fertilizers supply nitrogen, phosphorus and sodium to the soil.
Select the correct answer using the code given below:
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.
Vectors are living organisms that can transmit infectious pathogens between humans, or from animals to humans. The commonest vectors we all know are mosquitoes. Which among the following vector borne diseases are caused by mosquitoes?
1. Yellow Fever
2. Lymphatic Filariasis
3. Zika Fever
4. Japanese Encephalitis
Select the correct answer using the code given below:
Which of the following are the properties of the image formed by a plane mirror?
1. The image is always real and erect.
2. The size of the image is equal to that of the object.
3. The image formed is as far behind the mirror as the object is in front of it.
4. The image is laterally inverted.
Select the correct answer using the code given below.
Consider the following statements:
1.
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?