Consider the following statements:
1. The aperture of the pupil of a human eye can be changed with the help of the ciliary muscles.
2. The curvature of human eye cannot be changed, because the lens of a human eye is fixed.
Which of the statements given above is/are correct?
ANSWER: (D)
The Pupil
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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:
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?
Which of the following statement(s) is/are correct?
1. Saturated hydrocarbons are linked by only single bonds between the carbon atoms while unsaturated carbon compounds have double or triple bonds.
2. Saturated hydrocarbons generally give a clean flame while unsaturated carbon compounds give a yellow flame with lots of black smoke.
Select the correct answer using the code given below.
Consider the following statements about pesticide residue in our food chain:
1. It is introduced in the food chain by aquatic plants and animals.
2. These chemicals get accumulated progressively at each trophic level.
3. Human body accumulates minimum concentration of these chemicals.
Select the correct answer using the code given below:
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?
With reference to the uses of ‘concave mirrors’, read the following statements carefully:
1. They are commonly used in vehicles headlights to get powerful parallel beams of light.
2. They are often used as shaving mirrors to see a larger image of the face.
3. They are fitted on the sides of the vehicle to have a wider field of view.
4. Large concave mirrors are used to concentrate sunlight to produce heat in solar furnaces.
Which of the statements given above is/are correct?
With reference to ‘Magnetic Field’, consider the following statements:
1. The magnetic field produced by a current-carrying wire at a given point depends directly on the current passing through it.
2. The magnetic field inside a long straight solenoid-carrying current is zero.
Which of the statement(s) given above is/are correct?
Manure contains large quantities of organic matter and also supplies small quantities of nutrients to the soil. In this context, consider the following statements:
1. The organic matter in manure helps in improving the soil structure.
2. It increases the water holding capacity in sandy soils.
3. It causes water logging in clayey soils.
Select the correct answer using the code given below:
Consider the following statements:
1. Exchange of gases in plants occurs not only across the surface of leaves but also across the surface of stems and roots.
2. Plant close its pores known as the Stomata, when they do not need carbon dioxide for photosynthesis.
3. Guard cells present in plants are responsible for controlling the movement of water in them.
Which of the statements given above is/are correct?
Vaccines are now available for preventing a whole range of infectious diseases. Which among the following infectious diseases are preventable by the use of vaccine?
1. Polio
2. Measles
3. Whooping cough
4. Human Papilloma Virus (HPV)
Select the correct answer using the code given below: