List of top Science Questions

DNA is the basis of heredity. How?
What is covalent bond? Give two examples of it.
What is sinoauricular node?
Why is it necessary to balance a chemical equation?
What is ozone? Explain its importance.
Briefly describe the benefits of rainwater harvesting.
What is an ore?
What is corrosion? Explain with example.
Write the steps involved in the extraction of metals from ores.
Why does the aqueous solution of an acid conduct electricity?
How does the eye control the amount of light entering into it?
Prove for a concave mirror \[ \frac{1}{v} + \frac{1}{u} = \frac{1}{f} \]
Mention two reactions that displace chlorine from bleaching powder by giving equations.
Explain scattering of light.
How is the concentration of OH\(^-\) ion affected on adding a base in excess to sodium hydroxide solution?
What is the source of energy of the sun? Explain.
What is a non-renewable source of energy? Give two examples of it.
Which quantity remains constant in Ohm's law, when temperature is constant? Explain.
Write any two properties of magnetic field lines.
Find the power of a concave lens of 2 m focal length.
Write any three uses of a concave mirror.
Why is a rainbow colourful?
The device which directly converts solar energy into electricity is:
A bulb filament has a resistance of 1200 ohms. It is connected to a 220 V power supply. How much current will it draw?
The electromotive force of a cell is 1.5 V. The work done on passing a charge of 1 C will be: