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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 20Ω, 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. In figure, find the ammeter and voltmeter readings. ...

Q1. An electron beam has an aperture of 2 mm². A total of 7 × 10¹⁵ electrons flow through any perpendicular cross-section per second. Calculate the current density of the electron beam. Q2. The charge in a given wire varies with time, given by -     q = 3t³ - t² Where, q in 'C' and t in 'secs'. Find the current flowing in the wire at 4th second. Q3. The current flowing in a conductor is the function of time, given by -    I = 8t - 3 Where, I in 'Ampere' and t in'secs'. Find the total charge flowed in first 5 seconds in the conductor. Also, find the charge which flowed from 6th to 8th second. Q4. A storage battery of EMF 8 volt and internal resistance 0.5 ohm is being charged by a 120 volt dc supply using a series resistor of 15.5 ohm. What is the terminal voltage of the battery during charging? What is the purpose of having a series resistor in the charging circuit? Q5. The manufacturer sticker on an electric bulb reads 220 V, 60 W. If the s...