Living in the atmosphere of CO is dangerous because it
The inexhaustible source of energy of the stars is due to
Which one of the following statements is not true about cosmic rays?
Domestic cooking gas consists of mostly
H2O is liquid and H2S is a gas because
When soggy biscuits are kept inside the fridge for sometime they become crisp because
Consider the following statements and select the correct code.
Assertion (A): A chemical reaction becomes faster at higher temperature.
Reason (R): At higher temperature, molecular motion becomes more rapid.
Consider the following statements:
If there were no phenomenon of capillarity
1. It would be difficult to use a kerosene lamp.
2. One would not be able to use a straw to consume a soft drink.
3. the blotting paper would fail to function.
4. the big trees that we see around would not have grown on the earth.
Which of the statements given above are correct?
Hydrofluoric acid is not kept in glass bottles because it reacts with
The blue colour of water in the sea. What is the reason behind the phenomenon?
Which one of the following pairs is correctly matched?
Consider the following statements: Hard water is not suitable for
1. Drinking
2. Washing clothes with soap
3. Use in boilers
4. Irrigating crops
Which of these statements are correct?
Consider the following statements:
Assertion (A): LPG is a pollution free vehicular fuel.
Reason (R): Plying of CNG fuelled-buses is recommended for metropolitan cities in India.
What is the role of ultraviolet (UV) radiation in the water purification system?
1. It inactivates / kills the harmful micro- organisms in water.
2. It removes all the undesirable odours from the water.
3. It quickens the sedimentation of solid particles and improves the clarity of water.
Which of the statements given above is/are correct?
The difference between a nuclear reactor and atomic bomb is that
While tinning of brass utensils, the ammonium chloride powder used to clean the hot utensil produces fumes of
Which one of the following is not correct?
Which of the following substances is/are ozone depleting?
Select the correct answer from the codes given below:
1. Chlorofluorocarbons
2. Halons
3. Carbon tetrachloride
What is “ Kiss of death” ?
In the process of electroplating a utensil with zinc,
Hydrogen bomb is based on the principle of
Helium is preferred to hydrogen in air balloons because it
Acid rains is caused due to emission of which of the following into the atmosphere?
In cold weather, aquatic animals survive even when water to the top layer of the lake freezes into ice because