A wire 1.0m long and with cross-sectional area 2.0 x 10-7 m2 has a resistance of 0.1\(\Omega\). Calculate the electrical conductivity of the wire

5.0 x 107\(\Omega^{-1} m^{-1}\)

2.0 x 107\(\Omega^{-1} m^{-1}\)

5.0 x 107\(\Omega^{-1} m^{-1}\)

2.0 x 108\(\Omega^{-1} m^{-1}\)

5.0 x 108\(\Omega^{-1} m^{-1}\)

WAEC SSCE - Physics - 2008 (Objective)

Question 1 Report

The mass attached to a string is moving in a circular path. If the speed is doubled, the tension in the string will be

doubled

halved

four times as great

one-fourth as much

Answer Details

The tension in the string is related to the centripetal force required to keep the object moving in a circular path. According to centripetal force equation, F = mv²/r, where m is the mass of the object, v is the speed, and r is the radius of the circular path. Since the mass of the object remains constant, doubling the speed would increase the centripetal force required to keep it moving in a circular path by a factor of four (since F = mv²/r). Therefore, the tension in the string would also increase by a factor of four, so the correct answer is "four times as great."






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