How much work is done when one coulomb charge moves against a potential difference of 1 volt

How much work is done when one coulomb charge moves against a potential difference of 1 volt?

Charge given, Q = 1 CPotential difference, V = 1 V

Thus, the amount of work done, W in moving the charge is:

= 1 J

Concept: Potential and Potential Difference

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An electric lamp of 100 Ω, a toaster of resistance 50 Ω, and a water filter of resistance 500 Ω are connected in parallel to a 220 V source. What is the resistance of an electric iron connected to the same source that takes as much current as all three appliances, and what is the current through it?

Given,
Resistance of electric lamp, R1 = 100 Ω
Resistance of toaster, R2 = 50 Ω
Resistance of water filter, R3 = 500 Ω 

Equivalent resistance, Rp of the three appliances connected in parallel is given by,

            1Rp = 1R1+1R2+1R3

                  = 1100+150+1500= 16500

            Rp = 50016Ω      = 31.25 Ω 

Resistance of electric iron will be equivalent resistance of the three appliances connected in parallel = 31.25 Ω Applied voltage, V = 220 V 

Current through the appliance, I = VR = 220 V31.25Ω =7.04 A.