List of top Science Questions

The focal length of a converging lens is 20 cm. The power of this lens will be
The magnification produced by a convex mirror is always
The resistance of a wire of any substance of length \( l \) and area of cross-section \( A \) is 4 \( \Omega \). Another wire of the same substance has length \( 2l \) and area of cross-section \( \frac{A}{2} \). Then its resistance will be
Which of the following does not represent electrical power in a circuit?
When a beam of white light falls on the surface of a triangular glass prism it splits, after emerging out from the prism into various colours with different deviations. The colour which has minimum deviation is
A convex lens of focal length 10 cm forms a real image of the same size as the object. The distance between the object and its image will be:
What do you understand by corrosion? Give two measures for protection against it.
How are oxygen and carbon dioxide transported in humans?
What do you understand by Exothermic and Endothermic reactions? Give examples.
Write electronic configuration for the following elements:
(i) Sodium
(ii) Chlorine
Write an example of a combination reaction (write equation only).
Write short notes on the following:
(a) Acid rain
(b) Ductility and Malleability
(c) Micelle
Balance the following equations:
(i) Fe (s) + H2O (g) → Fe3O4 (s) + H2 (g)
(ii) C6H12O6 (aq) + O2 (aq) → CO2 (aq) + H2O (l)
On which factors does the force acting on a current carrying conductor placed in a magnetic field depend?
An object of length 2 cm is placed in front of a convex lens perpendicular to its axis, having focal length of 20 cm. Distance of the object from the lens is 30 cm. Find the position and nature of the image.
State the right-hand thumb rule for finding the direction of magnetic field associated with a current carrying conductor. Show the magnetic field lines due to a straight current carrying conductor.
What is the importance of fuse in electrical circuits? Total load of a house is 2200 W. Electricity is supplied at 220 V. What should be the rating of fuse used in the house? Write down the commercial unit of electrical energy.
Write the names of the wires used in the domestic electrical circuit and also write the colours of the insulating wires.
Write a short note on hypermetropia and its correction.
Which one of the following make up the food chain?
Give the formula for the focal length of a convex mirror. Give any two uses of the convex mirror.
Which one of the following is the main substance responsible for ozone layer depletion?
Why did Mendel conduct his experiment?
Pyruvate is oxidized in which part of the cell in presence of oxygen?
Explain the phenomenon of refraction of light.