The heat required to convert the unknown substance X from one phase to another is 1600 J times the specific heat of that substance.
Explanation:
The heat energy required to convert a substance or to heat up or increase the temperature of a substance can be obtained from the specific heat formula.
As per this formula, the heat energy applied should be equal to the product of mass of the substance with temperature gradient and also with specific heat of the substance. Basically, the heat provided to increase or convert a substance should be more than the specific heat of the substance.

Since, here the mass of the substance X is given as m = 20g and the temperature change is given from -10°C to 70°C.
Then ΔT = (70-(-10))=70+10=80°C.
As the substance is unknown, the specific heat of that substance can also not be determined. Hence keep it as C.

Q = 1600C J
Thus, the heat required to convert the unknown substance X from one phase to another is 1600 J times the specific heat of that substance.
Answer:
(B) (length)/(time³)
Explanation
The equation x = ½ at² + bt³ has to be dimensionally correct. In other words the term bt³ and ½ at² must have units of change of position = length.
We solve in order to find the dimension of b:
[x]=[b]*[t]³
length=[b]*time³
[b]=length/time³
Answer:
Water flowing rate= (300000kg/s) = (300000l/s)
Explanation:
First with the section of the channel, the depth of the water and the speed of the fluid we can determine the volume of fluid that circulates per second through the channel:
Volume per time= 15m × 8m × (2.5m/s)= 300 m³/s
With this volume of circulating fluid per second elapsed, we multiply it by the density of the water to determine the kilograms or liters of water that circulate through the channel per second elapsed:
Water flowing rate= (300m³/s) × (1000kg/m³)= (300000kg/s) = (300000l/s)
Taking into account that 1kg of water is approximately equal to 1 liter of water.
Answer:
<em>B) 1.0 × 10^5 V</em>
Explanation:
<u>Electric Potential Due To Point Charges
</u>
The electric potential produced from a point charge Q at a distance r from the charge is

The total electric potential for a system of point charges is equal to the sum of their individual potentials. This is a scalar sum, so direction is not relevant.
We must compute the total electric potential in the center of the square. We need to know the distance from all the corners to the center. The diagonal of the square is

where a is the length of the side.
The distance from any corner to the center is half the diagonal, thus


The total potential is

Where V1 and V2 are produced by the +4\mu C charges and V3 and V4 are produced by the two opposite charges of
. Since all the distances are equal, and the charges producing V3 and V4 are opposite, V3 and V4 cancel each other. We only need to compute V1 or V2, since they are equal, but they won't cancel.


The total potential is

