How many kilocalories is one kilojoule

How many kilocalories is one kilojoule

1 kJ equals 0.24 kcal
4.2 kcal equals 1 kJ
The voltage at both ends of a nickel chromium alloy wire is constant. When the nickel chromium alloy wire is evenly stretched, its resistance will decrease______ The current passing through it will______ (insert "larger", "smaller" or "unchanged")
When the nickel chromium alloy wire is evenly stretched, its length becomes longer and the wire becomes thinner, so the resistance becomes larger. Because the resistance becomes larger, the current through it will become smaller when the voltage is fixed
The resistance of a conductor composed of 7 copper wires of the same specification is 1 ohm; if it is connected to form the longest conductor, what is the resistance value of this conductor
Help!
If the resistance of single copper wire is R Ω, then: 1 / R + 1 / R + +1 / r = 1 (7 in total)
So r = 7 euro
The resistance of a wire is 7 * 7 = 49 Ω
Energy unit: how to convert electron volt to Joule?
1eV is the energy obtained by an electron through an electric field of 1 volt. Calculated by the electric potential energy formula: e = EU, e = 1.6 * 10 ^ - 19 (c), u = 1 (V), so e = 1.6 * 10 ^ - 19 (J) = 1eV
Electron volt EV is the number of elementary charges multiplied by the potential difference equal to joules
The name plate of an electric water heater is marked with "220V 1500W". When it is electrified for 1.5h, the electric energy consumed is
What is internal energy and how to calculate it?
What is the internal energy consumed?
220 V on the name plate indicates voltage and 150 W indicates power
And w = Pt = 150W * 1.5 * 3600s = 810000j
Internal energy refers to the sum of kinetic energy and potential energy in an object
Electric energy = 1500 * 1.5 * 3600 = 8100000 joules = 1.25 kWh
It's 2.25 degrees
If the nickel chromium alloy wire is connected to the circuit, the resistance will (increase / decrease / remain unchanged). If the nickel chromium alloy wire is folded and connected to the circuit, the resistance will (as above) be selected
The filament of a small light bulb is burnt out. The broken filaments are connected to the circuit together, and the lamp will become more stable than before
Nichrome wire in the circuit resistance - unchanged, so it is often used to make planting resistance
If the nickel chromium alloy wire is folded in half, the length of the access circuit becomes 1 / 2, and the cross-sectional area becomes twice. According to the resistance law, the resistance value is four times of the original
The filament of a small light bulb is burnt out. The length of the broken filament becomes smaller. According to the law of resistance, the resistance becomes smaller
According to P = u & # / R, the lamp will be brighter than before
1. The resistance does not change. The resistance is 1 / 4 of the original. Suppose that the original is 100 ohm, 50 ohm for each segment, 25 Ohm for two 50 ohm in parallel.
The current of the lamp will be shorter, and the resistance of the circuit will be smaller.
34 square millimeter copper wire, length is 20 meters, what is its resistance?
The resistivity of copper (18 ℃) P = 0.0168 Ω. (mm ^ 2) / M
Resistance R = PL / S = 0.0168 * 20 / 0.34 = 1 = 0.99 Ω
What a profound topic··
There is a "12V & nbsp; 6W" small bulb. If it is connected to 36V power supply and required to make it shine normally, it must______ Join one______ What is the electrical power consumed by this resistor______ W．
The current I = plul = 6w12v = 0.5A, the voltage at both ends of the series resistor U1 = u-ul = 36v-12v = 24V, so the series resistor R = u1i = 24v0.5a = 48 Ω, the electric power consumed by this resistor is p = u1i = 24V × 0.5A = 12W
Xiaowang's electric energy meter is marked with "220V 10A". The total power of his original electric appliances is 1500W
Recently, I bought a new electric water heater. Some data on the nameplate are shown in the table below
1) What is the rated current of the electric water heater?
(2) What is the resistance of the electric water heater in normal operation?
(3) After connecting the electric water heater to the home circuit, we can answer whether the household appliances can be used at the same time through calculation?
Although I didn't see the figure, I can tell you that it can be used. The 10A marked on the meter can allow the current of 20a. The current of 20a is about 4000W. The original 1500W, and at least 2500W. Generally, the water heater will not exceed 2500W, so it can be used
What is the resistivity of the conductor
The resistivity of copper conductor is 0.01851 Ω· mm2 / m
The calculation in Table 2 on page 4 of GB / t3956-2008 is as follows:
Resistivity section length kilometer resistance
0.018 0.5 1000 36
0.018375 0.75 1000 24.5
0.0181 1 1000 18.1
0.01815 1.5 1000 12.1
0.018525 2.5 1000 7.41
0.01844 4 1000 4.61
0.01848 6 1000 3.08
0.0183 10 1000 1.83
0.0184 16 1000 1.15
0.018175 25 1000 0.727
0.01834 35 1000 0.524
0.01935 50 1000 0.387
0.01876 70 1000 0.268
0.018335 95 1000 0.193
0.01836 120 1000 0.153
0.0186 150 1000 0.124
0.0183335 185 1000 0.0991
0.018096 240 1000 0.0754
0.01803 300 1000 0.0601
0.0188 400 1000 0.047
0.0183 500 1000 0.0366
0.017829 630 1000 0.0283
0.01768 800 1000 0.0221
0.0176 1000 1000 0.0176
According to the table, the resistivity varies. How much should be taken in the calculation
If the copper core material and ambient temperature remain unchanged, the resistivity will not change. You only need to calculate according to the following formula: r = R * L / s, where: R: resistance, in ohm, R: resistivity. For the copper core, it is the above data, that is: 0.01851 Ω· mm2 / ml: length of conductor, in meter (m)