Acid rains is caused due to emission of which of the following into the atmosphere?
The order of appearance of the following with increasing temperature during the refining of crude oil is
When soggy biscuits are kept inside the fridge for sometime they become crisp because
Hydrogen bomb is based on the principle of
Living in the atmosphere of CO is dangerous because it
Biogas mainly consists of
The inexhaustible source of energy of the stars is due to
What is “ Kiss of death” ?
Hydrofluoric acid is not kept in glass bottles because it reacts with
Which one of the following is not correct?
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?
Which one of the following statements is not true about cosmic rays?
Which one of the following sets of elements was primarily responsible for the origin of life on the Earth?
H2O is liquid and H2S is a gas because
Domestic cooking gas consists of mostly
The blue colour of water in the sea. What is the reason behind the phenomenon?
In the process of electroplating a utensil with zinc,
Consider the following parts of spectra:
1. Visible 2. Infrared 3. Ultraviolet 4. Microwave
Which of the following is the correct sequence in which the wavelengths increase?
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The difference between a nuclear reactor and atomic bomb is that
In cold weather, aquatic animals survive even when water to the top layer of the lake freezes into ice because
Which one of the following pairs is correctly matched?
A sample of chloroform before using as an anaesthetic, is tested by
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?
While tinning of brass utensils, the ammonium chloride powder used to clean the hot utensil produces fumes of