The old style (incandescent) light bulb converts more energy
into heat than it does into light. If you're using it mainly as a
source of light, then it's a bummer, and its efficiency is very low.
BUT ... if you're using an incandescent light bulb as a heater, then
its efficiency is much better. It all depends on your point of view.
Answer:
The formula that links energy and power is: Energy = Power x Time. The unit of energy is the joule, the unit of power is the watt, and the unit of time is the second.
Explanation:
Answer:
We know that force applied per unit area is called pressure.
Pressure = Force/ Area
When force is constant than pressure is inversely proportional to area.
1- Calculating the area of three face:
A1 = 20m x 10 m =200 Square meter
A2 = 10 mx 5 m = 50 Square meter
A3 = 20m x 5 m = 100 Square meter
Therefore A1 is maximum and A2 is minimum.
2- Calculate pressure:
P = F/ A1 = 30 / 200 = 0.15 Nm⁻² ( minimum pressure)
P = F / A2 = 30 / 50 = 0.6 Nm⁻² ( maximum pressure)
Hence greater the area less will be the pressure and vice versa.
Answer: V=IR
Explanation: for a series circuit connected to a battery supply, the total emf across the circuit is given as
E = I(R + r) and by expanding, we have that E =IR + It
Where r is the internal resistance of the battery
I is the total current flowing in the circuit
R total load resistance in the circuit.
E is the total emf of the circuit.
The total emf is the sum of 2 separate voltages.
"IR" which is the terminal voltage and "Ir" which is the loss voltage.
The teenila voltage is the voltage flowing in the circuit based on the equivalent resistance of the circuit while the loss voltage is the wasted voltage based on the internal resistance of the battery source.
Answer:
the mass of the body is 0.02 kg.
Explanation:
Given;
relative density of the oil,
= 0.875
mass of the object in oil,
= 0.013 kg
mass of the object in water,
= 0.012 kg
let the mass of the object in air = 
weight of the oil, 
weight of the water, 
The relative density of the oil is given as;

Therefore, the mass of the body is 0.02 kg.