Questions in Current Electricity

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A uniform wire of resistance $R$ is uniformly compressed along its length, until its radius becomes n times the original radius. Now resistance of the wire becomes
The resistance of a conductor is 5 ohm at $50^oC$ and 6 ohm at $100^oC$. Its resistance at $0^oC$ is
If an electron revolves in the path of a circle of radius of $0.5 \times 10^{–10}m$ at frequency of $5 \times 10^{15}$ cycles/s the electric current in the circle is (Charge of an electron = $1.6 \times 10^{–19} C$ )
Equal potentials are applied on an iron and copper wire of same length. In order to have the same current flow in the two wires, the ratio r (iron)/r (copper) of their radii must be (Given that specific resistance of iron = $1.0\times10^{-7}ohm–m$ and specific resistance of copper = $1.7\times10^{-8}ohm-m$)
An electron (charge = $1.6 \times 10^{–19}$ coulomb) is moving in a circle of radius $5.1 \times 10^{–11} m$ at a frequency of $6.8 \times 10^{15}$ revolutions/sec. The equivalent current is approximately
A rod of a certain metal is 1.0 m long and 0.6 cm in diameter. Its resistance is $3.0 \times 10^{-3}$ ohm. Another disc made of the same metal is 2.0 cm in diameter and 1.0 mm thick. What is the resistance between the round faces of the disc
At what temperature will the resistance of a copper wire become three times its value at $0^oC$ (Temperature coefficient of resistance for copper = $4 \times 10^{–3}$ per $^oC$)
An electron revolves $6 \times 10^{15}$ times/sec in circular loop. The current in the loop is
The charge of an electron is $1.6 \times 10^{–19}C$. How many electrons strike the screen of a cathode ray tube each second when the beam current is 16 mA
If potential $V=100\pm 0.5$ Volt and current $I=10\pm 0.2$ ampere given to us. Then what will be the value of resistance

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