A cylindrical resistor element on a circuit board dissipates 1.2 W of power. The resistor is 2 cm long, and has a diameter of 0.4 cm. Assuming heat to be transferred uniformly from all surfaces, determine (a) the amount of heat this resistor dissipates during a 24-hour period, (b) the heat flux, and (c) the fraction of heat dissipated from the top and bottom surfaces.

(a) The resistor disspates 103680 joules during a 24-hour period.

(b) The heat flux of the resistor is approximately 4340.589 watts per square meter.

(c) The fraction of heat dissipated from the top and bottom surfaces is 0.045.

Explanation:

(a) The amount of heat dissipated (), measured in joules, by the cylindrical resistor is the power multiplied by operation time (), measured in hours. That is:

(1)

If we know that and , then the amount of heat dissipated by the resistor is:

The resistor disspates 103680 joules during a 24-hour period.

(b) The heat flux (), measured in watts per square meter, is the heat transfer rate divided by the area of the cylinder (), measured in square meters:

(2)

(3)

Where:

- Diameter, measured in meters.

- Length, measured in meters.

If we know that , and , the heat flux of the resistor is:

The heat flux of the resistor is approximately 4340.589 watts per square meter.

(c) Since heat is uniformly transfered, then the fraction of heat dissipated from the top and bottom surfaces (), no unit, is the ratio of the top and bottom surfaces to total surface:

(3)

If we know that and , then the fraction is:

The fraction of heat dissipated from the top and bottom surfaces is 0.045.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards