Q. 22. A wire of resistivety ζ is stretched to three times to length. What will be its new resistivety?
Q. 23. Bends in a pipe slow down the flow of water through it. Do bends in a wire increase its electrical resistance?
Q. 24. The V-I graph for conductor makes angle with V-axis. Here V denotes voltage and I denote current. What is the resistance of this conductor? [Ans: R = cot ]
Q. 25. What are the factors on which the resistance of a conductor depends? Give the corresponding relation.
Q. 26. To reduce the brightness of a light bulb, should an auxiliary resistance be connected in series with it or in parallel?
Q. 27. Current is allowed to flow in a metallic wire at a constant potential difference. When the wire becomes hot, cold water is poured on half of its portion. By doing so, its other becomes still more hot. Explain its reason.
Q. 28. What is super-conductivity? Write its two application.
Q. 29. Prove that in parallel combination of electrical applications, total power consumption is equal to the sum of the powers of the individual appliances.
Q. 30. A current in a circuit having constant resistance is tripled. How does this effect the power dissipation?
Q. 31. A wire connected to a bulb glows when same current flows through them. Why?
Q. 32. Nichrome and cupper wires of the same length and diameter are connected in series in the electric circuit in which wire, the heat will be produced at higher rate? Explain.
Q. 33. Draw V-I graph for an Ohmic and Non-Ohmic material. Give one example for each.
Q. 34. How does the resistivety of
Q. 35. There is an impression among many people that a person touching a high power line gets stuck with the line. Is that true? Explain.
Q. 36. Explain why an electric bulb becomes dim when an electric heater in parallel circuit is made on. Why dimness decreases after some time?
Q. 37. Long distance power transmission is carried on high voltage lines. Why?
