List of top Science Questions

Mention the pathway of urine starting from the organ of its formation. Name any two substances which are reabsorbed from the initial filtrate in the tubular part of the nephron.

How does the embryo get nourishment inside the mother’s body? Explain briefly.

List two functions each of the following parts of the human female reproductive system: (1) oviduct (2) uterus (3) ovary

List three advantages of practising the process/technique by the farmers.

What is vegetative propagation? Is this process sexual or asexual? Justify your answer.

Name and explain the process used to obtain sodium hydroxide from the aqueous solution of sodium chloride (Brine). Name the two gases which are given at the anode and the cathode respectively. List two uses of each of these gases.

An electrical heater of resistance 10 Ω draws a steady current of 5 A from the service mains for 2 hours. Find the power of this heater and the amount of energy consumed by the heater in kilowatt-hour.

Select two plants from the following which are obtained by this technique: Banana, Papaya, Jasmine, Mustard

Obtain an expression for the amount of heat produced in a conductor of resistance R when a steady current I flows through it for a time t.

The resistance of a metallic wire of 100 m is 20 \(\Omega\). If the radius of the wire is 5 mm, find the resistivity of the metal of the wire.

Name the plant growth hormone which is synthesized at the shoot tip. Explain why the shoot of a potted plant bends towards light coming from a window.

Is it possible that a trait gets inherited, but not expressed? Give an example to justify your answer.

What does a food chain represent? “The number of trophic levels in a food chain is limited.” Give an example stating reason to justify this statement.

What are decomposers? Explain how the decomposers (i) keep the environment clean, and also (ii) replenish the soil nutrients.

Name the (i) hormone released, and the (ii) gland which secretes it in human beings during scary situations. Explain how our body responds to enable it to deal with such situations.

Write the relation between resistivity (\(\rho\)) and resistance (\(R\)) for a uniform metallic conductor of length (\(l\)) and area of cross-section (\(A\)). Use this relation to obtain the SI unit of resistivity.

With the help of chemical equations, differentiate between roasting and calcination. How is metal reduced from the product obtained after roasting/calcination of the ore? Write the chemical equation for the reaction involved.

For distant transmission of electric power, an alternating current (ac) is considered to be advantageous over direct current (dc). Why?

Consider the following organic compounds:
\[ C_2H_5CHO, \, CH_3COOH, \, C_2H_5OH, \, CH_3COCH_3 \]
Which one of these compounds, when heated at 443 K in excess conc. \(\text{H}_2\text{SO}_4\), forms ethene as its major product? State the role of conc. \(\text{H}_2\text{SO}_4\) in the reaction. Also, write the chemical equation for the chemical reaction involved.

When and where does a rainbow appear in the sky? List the phenomena of light in proper sequence which occurs during the formation of a rainbow. Why can a rainbow not be seen from the surface of the moon?

Name and explain the most widely used method for refining impure metals.

Name and state the rule for determining the direction of force on a current carrying conductor placed in a magnetic field.

A straight conductor is suspended horizontally with its axis perpendicular to the magnetic field of a strong horseshoe magnet. The conductor gets displaced towards the right when a steady current is passed through it. What will happen to the displacement of the conductor if:

1. Polarity of the horseshoe magnet is reversed?
2. Direction of current in the conductor is reversed?
3. Current through the conductor is increased?

How is the type of current used in household supply different from the one given by dry cells or storage batteries?

Consider the following organic compounds:
\(\text{C}_2\text{H}_5\text{CHO}, \text{CH}_3\text{COOH}, \text{C}_2\text{H}_5\text{OH}, \text{CH}_3\text{COCH}_3\)
Give the chemical equation for the chemical reaction when \(\text{CH}_3\text{COOH}\) and \(\text{C}_2\text{H}_5\text{OH}\) react in the presence of conc. \(\text{H}_2\text{SO}_4\).