Recent content by A90

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    Electric field strength from a light bulb

    Homework Statement What is the approximate electric field strength of the electromagnetic waves radiated by a 100-W light bulb, measured 3.0m from the bulb? Homework Equations $$\vec{E}=\frac{kq}{d^{2}}$$ $$P=\frac{2kq^{2}a^{2}}{3c^{3}}$$ The Attempt at a Solution I solved for...
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    Calculating Capacitance for a Light-Bulb and Capacitor Circuit

    We have learned it with electric potential, rather than electric current, but I can see how one implies the other. With the data given I found I_0 (sorry, subscript keeps coming out as superscript- that is 'I naught') to be .3, but I'm not sure about I(t).
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    Calculating Capacitance for a Light-Bulb and Capacitor Circuit

    Is that assuming dQ=Q and dt=10? I get: I=(Δϕ)/R=dQ/dt then, dQ=I*dt=(Δϕ*dt)/(R*Δϕ)=dt/R=1 The answer is supposed to be 1.4 F
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    Calculating Capacitance for a Light-Bulb and Capacitor Circuit

    Homework Statement Imagine that you have a light-bulb that has a resistance of about 10 Ω and that can tolerate a maximum voltage of 3 V. Imagine that you want to connect this to a charged capacitor large enough to keep the bulb glowing reasonably brightly for more than 10s. Roughly what...