List of top Science Questions

Which signals will get disrupted in case of a spinal cord injury?
Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
The brain is responsible for
The gap between two neurons is called a
Which of the following is a plant hormone?
A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.
Differentiate between parenchyma, collenchyma and sclerenchyma on the basis of their cell wall.
How are simple tissues different from complex tissues in plants?
How many types of elements together make up the xylem tissue? Name them.
Define the term “tissue”.
What do you mean by a precipitation reaction? Explain by giving examples.
An artificial satellite is moving in a circular orbit of radius 42250 km. Calculate its speed if it takes 24 hours to revolve around the earth.
Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
A ball is gently dropped from a height of \(20\) \(m\). If its velocity increases uniformly at the rate of \(10\) \(m s^{-2}\), with what velocity will it strike the ground? After what time will it strike the ground?
In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?
What are amphoteric oxides? Give two examples of amphoteric oxides.
In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write down the reaction involved.
You are given a hammer, a battery, a bulb, wires and a switch.
  1. How could you use them to distinguish between samples of metals and non-metals?
  2. Assess the usefulness of these tests in distinguishing between metals and non-metals.
A motorboat starting from rest on a lake accelerates in a straight line at a constant rate of \(3.0\) \(m s^{–2}\) for \(8.0\) \(s\). How far does the boat travel during this time?
Food cans are coated with tin and not with zinc because
What is the difference between displacement and double displacement reactions? Write equations for these reactions.
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.