Sources of Energy — Science STD 10 — Question

What is the relation between the focal length and radius of curvature of a spherical mirror (concave mirror or convex mirror)? Calculate the focal length of a spherical mirror whose radius of curvature is 25cm.

What happens to the moonflower

1. During daytime, and
2. At night ? What is this phenomenon known as?

An electric room heater draws a current of 2.4A from the 120V supply line. What current will this room heater draw when connected to 240V supply line?

What is phloem tissue? Phloem contains two types of cells joined side by side. Name these two types of cells. State whether these cells are living or dead.

Explain the terms ‘self pollination’ and ‘cross-pollination’?

What are the functions performed by the testis in human beings?

How can the wastes such as paper, plastic and metal objects be disposed of?

Helium and neon are unreactive gases. What, if anything, do their atoms have in common?

An object is placed just outside the principal focus of concave mirror. Draw a ray diagram to show how the image is formed, and describe its size, position and nature.

When the material A mined from the earth is heated strongly in an insufficient supply of air, it produces a solid fuel B which consists mainly of carbon. When another material C obtained from trees is heated in an insufficient supply of air, it produces another solid fuel D which also consists mainly of carbon. Name A, B, C and D.