It really depends on what the bulb is being used for, since efficiency means how much of the output is USEFUL.
If the bulb is being used for light in a dark room, then it produces (8.2% x 21W) = 1.72 joules per second of light energy.
If the bulb is being used to keep a hamster cage or a fish tank warm, then the 8.2% is the useful part, and the light is the other (91.8% x 21W) = 19.28 joules per second.
We can use the equation of
E = mc△T
To calculate the total heat absorbed.
E is the total heat absorbed (energy used)
m is mass.
c is specific heat capacity and
△T is the temperature change.
E = 125 x 4.184 x (32.8 - 25.2)
E = 3974.8 J
Therofre the total heat absorbed is 3974.8 joules.
Explanation:
Usually when we think of waves, we think of transverse waves. These are waves where points move up and down perpendicular to the motion of the wave. Examples include water waves, whipping a rope, or even doing the "wave" in a crowd. You can think of these as "two dimensional" waves.
Longitudinal waves are waves where points move left or right, parallel to the motion of the wave. In other words, there is compression and expansion of the medium. Examples include sound waves, or pulses in a slinky.
Answer:
KE= 1/2mv^2= 1/2*0.0042kg*993m/s= 2.0853joule
