Secondary School (English Medium) (5 to 8) कक्षा ७ - CBSE Question Bank Solutions for Science

The rearing of silkworms for obtaining silk is called ______.

Selective breeding is a process of ______.

Hair trap a lot of ______, which is a poor ______ of heat.

Explain the phrase – “Unity is Strength” on the basis of the making of fabric from fibre.

Write various steps for processing fibres into wool.

A marble tile would feel cold as compared to a wooden tile on a winter morning because the marble tile ______.

To keep her soup warm Paheli wrapped the container in which it was kept with a woollen cloth. Can she apply the same method to keep a glass of cold drink cool? Give reason for your answer.

A circular metal loop is heated at point O as shown in the following figure.

1. In which direction would heat flow in the loop?
2. In which order are the pins at points P, Q and R fixed with the help of wax fall if points O, P, Q and R are equidistant from each other?

In the arrangements A and B shown in the following figure, pins P and Q are fixed to a metal loop and an iron rod with the help of wax. In which case are both the pins likely to fall at different times? Explain.

Observe the picture given in figure. Water is being boiled in a pan of wide base.

1. Which position P or T will feel warmer?
2. Fill up the boxes P and T to indicate the mode of flow of heat to the hand.

The correct way of making a solution of acid in water is to ______.

Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed

Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are ______.

Which of the following set of substances contain acids?

Which of the following is an acid-base indicator?

State whether the following statement is true or false. Correct the false statement.

All substances are either acidic or basic.

State whether the following statement is true or false. Correct the false statement.

A compound if acidic will turn all indicators red.

State whether the following statement is true or false. Correct the false statement.

Lemon water is basic in nature.

Paheli is suffering from indigestion due to acidity. Is it advisable to give her orange juice in this situation and why?

While playing in a park, a child was stung by a wasp. Some elders suggested applying paste of baking soda and others lemon juice as remedy. Which remedy do you think is appropriate and why?