771. The area under the force displacement graph represents__________________?
A. area
B. work done
C. power
D. none of these

772. Propulsion force of a rocket is____________________?
A. non-conservative force
B. conservative force
C. both A and B
D. none of these

773. Geothermal energy is a _______________________ source of energy?
A. non-renewable
B. stable
C. renewable
D. none of the above

774. ________________ cells converts solar energy into electrical energy?
A. rotory
B. photovoltaic
C. galvanic
D. non of these

775. Biomass can be converted into fuels by____________________?
A. direct combustion
B. fermentation
C. both A and B
D. none of these

776. Which of the following substances posses the highest elasticity ?
A. Rubber
B. Steel
C. Glass
D. Copper

777. What are the dimensions of stress ?
A. MLT-2
B. ML-2T-1
C. ML-1T-2
D. ML-T-1

778. Which one of the following physical quantities does not have the dimensions of force per unit area ?
A. Stress
B. Strain
C. Youngs modulus
D. Pressure

779. A wire of length L is stretched by a length E when a force F is applied at one end. If the elastic limit is not exceeded the amount of energy stored in the wire is_________________?
B. (FE)
C. FE2/L
D. FE2

780. When a force is applied at one end of an elastic wire it produces at strain ∝ in the wire. If y is the young’s modulus of the material of the wire the amount of energy stored per unit volume of the wire is given by_________________?
A. Y∝
B. 2Y∝
C. Y∝/2
D. Y∝2