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?
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Which among the following method(s) is/are used by pests to attack crops sown in the field?
1. They attack the root of the plant.
2. They bore into stem and fruits of the plant.
3. They suck water from various parts of the plant.
Select the correct answer using the code given below:
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?
Read the following statements carefully and select the correct answer from codes given below:
1. The phenomenon of splitting of white light into its seven component colours by a prism is called dispersion.
2. While passing through a prism, the violet light bends the least while the red the most.
3. Isaac Newton was the first to use a glass prism to obtain the spectrum of sunlight.
Which of the statements given above is/are correct?
Which among the following are the characteristic features of birds?
1. They are cold-blooded animals.
2. They lay eggs.
3. Two forelimbs are modified for flight.
4. They breathe through lungs.
Select the correct answer using the code given below:
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.
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.
In the question given below, there are two statements marked as Assertion (A) and Reason (R). Read the statements given below carefully:
Assertion (A): The Sun at the sunrise or the sunset appears red whereas at noon, the Sun appears white.
Reason (R): Light from the Sun near the horizon passes through larger distance in the earth’s atmosphere than the light from the Sun overhead.
Choose the correct answer using the codes given below:
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?
1. Which of the following statement(s) in the context of ‘Human Eye’ is/are NOT correct?
1. Most of the refraction of the light rays entering the eye occurs at the outer surface of the crystalline lens.
2. Iris is a dark muscular diaphragm that controls the size of the pupil.
3. Pupil regulates and controls the amount of light entering the eye.
4. Retina is a delicate membrane having enormous number of light-sensitive cells.
Select the correct answer using codes given below:
According to Archimedes’ principle - When a body is immersed fully or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by it. Which among the following are based on the application of this principle?
1. Ships
2. Lactometer
3. Thermometer
Select the correct answer using the code given below: