Secondary School (English Medium) (5 to 8) इयत्ता ८ - CBSE Question Bank Solutions for Science

Identify the lightning conductor and the copper plate in the following figure.

If the materials used for constructing a building were good conductors, do you think lightning will strike the building. Will the lightning conductor be still required to be installed in the building?

You might have observed on a dry day that when you touch the screen of a television or computer monitor (with picture tube), you get a slight shock. Why does it happen?

Explain how does lightning conductor protects a building from getting struck by lightning.

Explain how lightning takes place.

Explain why it is safer to use a wireless telephone instead of a landline telephone during lightning.

What precautions would you take if lightning occurs while you are outside the house?

Plastics are flexible and waterproof and some are even UV resistant.

Suppose you are outside your home and an earthquake strikes. What precaution would you take to protect yourself?

List three states in India where earthquakes are more likely to strike.

Earthquakes can be predicted in advance.

Name the scale on which the destructive energy of an earthquake is measured. An earthquake measures 3 on this scale. Would it be recorded by a seismograph? Is it likely to cause much damage?

Assertion and Reason

A: It takes a very long time for nylon clothes to breakdown into microfibers but cotton clothes need only six months to decompose.

R: Nylon made out of petrochemicals is non-biodegradable and cotton cloth is biodegradable.

Which of the following is not a common property of plastics?

Plastic is used for making a large variety of articles of daily use and these articles are very attractive. But it is advised to avoid the use of plastic as far as possible. Why?

Select the articles from the following list which are biodegradable.

1. paper
2. woolen clothes
3. wood
4. aluminium can
5. plastic bag
6. peels of vegetables

Indicate whether the following statement is True or False. Also write the false statement in their correct form.

Most of the plastics are biodegradable

Despite being very useful, it is advised to restrict the use of plastic. Why is it so? Can you suggest some methods to limit its consumption?

Generally metallic oxides are basic and non-metallic oxides are acidic in nature. Solution of which of the following oxides in water will change the colour of blue litmus to red?

Which non-metal is used to disinfect water?