536: In which State is the Guru Shikhar Peak located ?

(a) Maharashtra
(b) Rajasthan
(c) Madhya Pradesh
(d) Gujarat
537: When iron rusts, the weight:

(a) Increases

(b) Decreases

(c) Remains the same

(d) First increases then decreases
538: Ajanta Caves are located in the State of:

(a) Maharashtra

(b) Gujarat

(c) Tamil Nadu

(d) West Bengal
539: The following are the rulers of the slave dynasty:

I. Ghiyas-ud-din Balban

II. Iltutmish

III. Qutb-ud-din Aibak

IV. Nasir-ud-din Mahmud

The correct order in which these sultans ruled over India is

(a) II, III, I, IV

(b) I, IV, II, III

(c) IV, I, II, III

(d) III, II, IV, I
540: Mixture of which one of the following pairs of gases is the cause of occurrence of most of the explosions in mines?

(a) Hydrogen and oxygen

(b) Oxygen and acetylene

(c) Methane and air

(d) Carbon dioxide and methane