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Electricity - Extra questions Q1. Find the heat generated in a wire of resistance 100Ω connected to a constant voltage supply of 80 volts for 15 seconds. Q2. An electric iron of rating 200V, 4A is connected to a suitable 200V voltage source. If a fan with power consumption 100W is connected to the iron with an independent switch. Calculate - (i) Current for the entire circuit. (ii) Resistance of the entire circuit. Q3. Find the resistivity of a wire with resistance 200Ω, length 2 m and having cross-sectional area 2.5 mm². Q4. Which has more resistivity : a thin copper wire at 30°C or a thick copper wire at 30°C? Q5. Which has more resistivity : a copper wire at 30°C or an aluminium wire at 30°C? Q6. Which has more resistivity : a copper wire at 30°C or a copper wire at 42°C with same length and diameter? Q7. Calculate the resistance of a wire with resistivity 2 × 10-⁶ Ωm, length 5 m and diameter 2 mm. Take, π = 3.14 Q8. How many 10 Ohms resistors are required to make an equivale

Q1. A bus covered 40% distance of its initial journey at a speed of 15 m/s, next 20% of its journey at a speed of 40 m/s and remaining journey at a speed of 25 m/s. Find the average speed of the bus in the entire journey. Ans. 20.9 m/s Q2. A car maintained a speed of 30 m/s in half of its journey time, 20 m/s in quarter time of its journey and 10 m/s in remaining time of its journey. Find the average speed of the car in its full journey. Ans. 22.5 m/s Q3. Aakash while driving to school, computes the speed for his trip to be 25 km/h. On his return trip along the same route, there was less traffic and the speed was 40 km/h. Find the average speed of Aakash's trip. Ans. 30.7 km/h by    www.advguruji.blogspot.com