6. Which of the following statements is/are true?*

A concave lens has 4 dioptre power having a focal length 0.25 m
A convex lens has 4 dioptre power having a focal length 0.25 m
A concave lens has - 4 dioptre having a focal 0.25 m
A convex lens has -4 dioptre power having a focal length 0.25 m

The metric unit of electrical power is the watt volt ampere ohm

Abearing is designed to a reduce friction b. support a load c.guide moving parts such as wheels, shafts and pivots d. all of the above

Suppose that two tanks, 1 and 2, each with a large opening at the top, contain different liquids. a small hole is made in the side of each tank at the same depth 1.57 m below the liquid surface, but the hole in tank 2 has 2.49 times the cross-sectional area of the hole in tank 1. (a) what is the ratio ρ1/ρ2 of the densities of the liquids if the mass flow rate is the same for the two holes? (b) what is the ratio rv1/rv2 of the volume flow rates from the two tanks? (c) at one instant, the liquid in tank 1 is 14.9 cm above the hole. if the tanks are to have equal volume flow rates, what height above the hole must the liquid in tank 2 be just then?