Energy — PHYSICS STD 7 — Question

Explain the following :Why are ice blocks wrapped in saw dust of woolen blanket?

Given below stament is incorrect. Write the correct statement :
A graduated cylinder is used to measure the volume of sand.

Arrange the following substances in order of their increasing density:
(a) iron
(b) cork
(c) brass
(d) water
(e) mercury

Given below statement is incorrect. Write the correct statement :
In case of uniform speed, one can need to find the average speed of the body.

Given below statement is incorrect. Write the correct statement :
Heat from the sun reaches the earth by the process of convection.

Name a domestic device in which an electromagnet is used ?

Give an example where electrical energy gets converted to sound energy.

Given below statement is incorrect. Write the correct statement :
Shining bodies are good absorbers and good radiators of heat energy.

A musician recognizes the musical instrument by hearing the sound produced by it, even without seeing the instrument. Which characteristic of sound makes this possible ?