WSCGroup5

The diameter of a sphere is 6 cm. It is melted and drawn into wires of diameter 2 mm. The length of wire is

• 12 m
• 18 m
• 36 m
• 66 m

An electric fuse works on the /

• heating effects of the current
• magnetic effect of current
• lighting effects of current
• chemical effects of current

The substance having infinitely high resistance is called

• conductor
• insulator/
• superconductor/
• resistor/

The ratio of the length of a rod and its shadow is 1:√3. the angle of elevation of the sum is

• 30 deg
• 45 deg
• 60 deg
• 90 deg

A quadratic equation whose one root is 2 and the sum of roots is zero, is

• x2+4=0
• x2 - 4=0
• 4x2 - 1=0
• x2 - 2=0

Find the distance between the points P (-6,7) and Q(-1, -5).

• 25
• 19
• 13
• none of these

The radius of wire is 0.24 mm. Then its area of cross section taking significant figures into consideration is

• 0.1 mm2
• 0.2 mm2
• 0.18 mm2
• 0.180 mm2

Which of the following term does not represent electric power in an electric circuit?

• I2R
• IR2
• VI
• V2/R

The resistivity of copper metal depends on only one of the following factor, this factor is

• length
• area of cross-section
• temperature
• thickness/

The SI unit of energy is

• joule/
• coulomb/
• watt/
• ohm meter