866: The working principle of a washing machine is
(a) centrifugation
(b) dialysis
(c) reverse osmosis
(d) diffusion
867: Unit of distance used in navigation is:
(a) Nautical mile
(b) Kilometre
(c) Light year
(d) Yard
868: How many High Courts in India have jurisdiction over more than one State (Union Territories not included)?
(a) 2
(b) 3
(c) 4
(d) 5
869: Physiological population density is the ratio of:
(a) Total population to total area
(b) Total population to total irrigated land area
(c) Total population to urban land area
(d) Total population to rural land area
870: A person walking barefooted in a field feels a sharp sting and on examination two puncture marks are found on his leg. He is most probably bitten by:
(a) Poisonous snake
(b) Non-poisonous snake
(c) Scorpion
(d) Rat