17-21

The unit of work or energy in S.I. units is

• (a) newton
• (b) pascal
• (c) kilogram meter
• (d) watt
• (e) joule.

Forces are called concurrent when their lines of action meet in

• (a) one point
• (b) two points
• (c) plane
• (d) perpendicular planes
• (e) different planes.

The lithosphere is approximately thick.

• (a) 50-100 km
• (b) 100-200 km
• (c) 5-10 km
• (d) 1-2 km

Diamond is having hardness number

• (a) 10
• (b) 7
•  (c) 1
• (d) 2

Cleavage means

•  (a) development of crystal faces during mineral growth
• (b) Splitting a mineral along planner surfaces
• (c) development of irregular fractures when minerals is broken
• (d) density and specific gravity of minerals.<br />

What is the molten rock under the earth's surface called ?

• (a) magma
• (b) lava
•  (c) both lava and magma
• (d) none of these<br />

The curve representing ohm's law is

• a. sine function
• b. Linear
• c. a parabola
• d. a hyperbola

The resistance of a conductor having length l area of cross section a and resistivity ? is given as:

• a. pa/l
• b. pl/a
• c. pla
• d. l/p

The resistance of wire varies inversely as

• a. area of cross section
• b. length
• c. resistivity
• d. temperature

Three resistors, each of R ohms, are connected to form a triangle. The resistance between any two terminals will be:

• a. 2/3 R
• b. 3/2R
• c. R
• d. 3R