Atoms and Molecules — Science STD 9 — Question

While preparing a slide for observing onion peel under a microscope, the onion peel is immediately kept in a watch-glass containing a drop of water. Why this is done?

Which of the following is not an example of simple tissue in plants?

1. Parenchyma
2. Collenchyma
3. Xylem
4. Sclerenchyma

Gold is chosen by Rutherford for his α-ray scattering experiment because:

In which of the following cases of motion, the distance moved and the magnitude of displacement are equal?

Four students A, B, C and D find the acceleration due to gravity at the top of Ooty, Nainital, Mount Everest and Shimla. The acceleration due to gravity is the least:

During purification of water, which of the following step (s) is incorrect?

1.008 grams of hydrogen combines with 35.453 g of chlorine to form 36.463 g of a pure compound (hydrogen chloride). Dalton's explanation for this experimental fact might be: 

Which of the following symbol of elements is not taken from Latin names:

A mixture of milk and ground oil can be separated by:

A microphone converts:

1. Electrical energy into sound energy in ordinary telephone.
2. Microwave energy into sound energy in a mobile phone.
3. Sound energy into mechanical energy in a stereo system.
4. Sound energy into electrical energy in public address system.