Calculate AC Circuit Power: Toaster 3A, 240V, 50Hz

  • Thread starter Thread starter frozen7
  • Start date Start date
  • Tags Tags
    Circuit
AI Thread Summary
An electric toaster operates at 3A rms current and 240V, 50Hz, allowing for the calculation of average power using the formula P(average) = I(rms) x V(rms) cos φ. The power factor is not specified but is likely unnecessary for this calculation. Given that the toaster's heating element is purely resistive, the power factor can be assumed to be one. This means all energy is converted to heat without any phase shift between voltage and current. Thus, the average power can be calculated directly without needing to consider a power factor.
frozen7
Messages
163
Reaction score
0
An electric toaster draws 3A rms current from a 240V, 50Hz source. Calculate the average power and peak value of the instantaneous power to the toaster.

P(average) = I (rms) x V (rms) cos \phi

Since the power factor is not mentioned in the question. Can the question be solved?
 
Physics news on Phys.org
If the power factor isn't given, it probably isn't needed. What would you guess the power factor of a toaster to be? What is the heating mechanism?
 
Is it because all the energy become heat so the power factor is equal to one ?
 
Yeah. The heating element is purely resistive, and the power factor of a resistive circuit is unity. You only get a phase shift between the applied voltage and resulting current if the load is reactive.
 
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top