The chemical formula for plaster of paris is:

In a double displacement reaction such as the reaction between sodium sulphate solution and barium chloride solution:

(A) exchange of atoms takes place (B) exchange of ions takes place

(C) a precipitate is produced (D) an insoluble salt is produced

The correct option is:

Baking soda is a mixture of:

The laws of reflection hold true for:

A. plane mirrors only B. concave mirrors only

C. convex mirrors only D. all reflecting surfaces

OR

When an object is kept within the focus of a concave mirror, an enlarged image is formed behind the mirror. this image is:

A. real B. inverted

C. virtual and inverted D. virtual and erect

At the time of short circuit, the electric current in the circuit:

A. vary continuously B. does not change

C. reduces substantially D. increase heavily

OR

Two bulbs of 100 W and 40 W are connected in series. The current through the 100 W bulb is 1 A. The current through the 40 W bulb will be:

A. 0.4 A B. 0.6 A

C. 0.8 A D. 1 A