PLEASE HELP PHYSICS EXAM An energy input of 1.3 × 1018 J is supplied each year by power stations to the National Grid.

Not all of this energy is supplied to consumers. Some of the energy is wasted in the distribution process.

Write the equation which links efficiency, total input energy transfer and useful output

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energy transfer.

The energy supplied each year to consumers is 1.2 × 1018 J Calculate the efficiency of the distribution process.

[1 mark]

The graph represents the distance a car travels over time while on the highway. which statement about the car's trip is accurate? a) the car does not move over time. b) the car travels at a constant velocity. c) the car's velocity increases constantly over time. d) the car's velocity decreases constantly over time.

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.

Aphoton is absorbed by an electron that is in the n = 3 state of a hydrogen atom, causing the hydrogen atom to become ionized. very far away from the nucleus, the released electron has a velocity of 750,000 m/s. what was the wavelength of the absorbed photon?