Work And Energy — Science STD 9 — Question

The anion of an element has:

Before playing the orchestra in a musical concert, a sitarist tries to adjust the tension and pluck the strings suitably. By doing so he is adjusting:

Which of the following group of plants is called vascular cryptogams?

1. Thallophyta.
2. Bryophyte.
3. Pteridophyta.
4. Angiospermae.

A sprinter is running along the circumference of a big sports stadium with constant speed Which of following do you think is changing in this case?

1. Magnitude of acceleration being produced.
2. Distance covered by the sprinter per second.
3. Direction in which the sprinter is running.
4. Entripetal force acting on the sprit.

‘A’ has 9 protons, 9 electrons and 10 neutrons. 'B' has 12 protons, 12 electrons and 12 neutrons. Formula between A and B is:

A few substances are arranged in the increasing order of ‘forces of attraction’ between their particles. Which one of the following represents a correct arrangement?

Which one of the following is incorrect about tuberculosis?

1. It is caused by Salmonella.
2. It commonly affects lungs.
3. Bacteria release tuberculin toxin.
4. Patient's sputum contains blood.

The innermost layer of cortex which has casparian thickenings in its cells is the

Haversian canals are present in:

The epidermal cells of onion protect against: