Metals and Non-Metals — Science STD 10 — Question

Why are traits acquired during the life-time of an individual not inherited?

An electric kettle rated at 220V, 2.2kW, works for 3 hours. Find the energy consumed and the current drawn.

Explain why:
Covalent compounds have generally low melting points.

What is the position of the image when an object is placed at a distance of 20cm from a concave mirror of focal length 20cm?

Write Einstein’s mass-energy equation. Give the meaning of each symbol which occurs in it.

Solar cells are used to provide the electric current to charge the batteries of a car driven by an electric motor. Describe the energy changes which take place.

How would you test for an alcohol?

Write one use of wind energy.

1. In the past.
2. At present.

A student prepared solutions of (i) an acid and (ii) a base in two separate beakers. She forgot to label the solutions and litmus paper is not available in the laboratory. Since both the solutions are colourless, how will she distinguish between the two?

“Burning of fossil fuels results in global warming". Give reasons to justify this statement.