A. A
B. l
C. A2
D. Both A. & B.
Related Mcqs:
- A semi-conductor is damaged & behaves like a conductor, on passing a strong electric current through it, because it heats up the crystals & breaks the covalent bonds resulting in _______________ electrons ?
A. Lack of free
B. Excess of
C. Decrease in
D. None of these - The ratio of thermal & electrical conductivity is same for all the metals at the same temperature; and at around room temperature, this ratio is proportional to(where, T = absolute temperature, °K) ?
A. T
B. 1/T
C. T2
D. 1/T2 - In electrical resistance welding, distortion results from the use of improper________________?
A. Clamping methods
B. Electrodes
C. Current
D. Filler material - The pressure drop per unit length for laminar flow of fluid through a long pipe is proportional to (where, A = cross-sectional area of the pipe & D = Diameter of the pipe) ?
A. A
B. D
C. 1/A
D. 1/A2 - Out of the following, the ________________ pipe has the least corrosion resistance?
A. Mild steel
B. Copper
C. Cast iron
D. Wrought iron - Solidification time of a molten metal in a casting is proportional to (where, V = volume of metal & A = its surface area; in the casting) ?
A. V/A
B. V/A2
C. V2/A
D. V2/A2 - Wave length of X-rays is about 1 angstrom; however it cannot pass through a sheet of ________________?
A. Paper
B. Cloth
C. Lead
D. Aluminium - Electrical conductivities of semi-conductors are of the order of ______________ ohm/cm ?
A. 10-3
B. 103
C. 10-15
D. 1015 - Direct conversion of thermal energy to electrical energy is facilitated by the____________________?
A. Fuel cells
B. Photo voltaic cell
C. Magneto hydrodynamic generator
D. None of these - Which of the following materials has the poorest electrical conductivity ?
A. Carbon
B. Aluminium
C. Silver
D. Stainless steel
