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