Two lamps with a resistance of 240 ohms are connected in series and connected to a mains voltage of 220 V. What is the current strength in each lamp? 13. During the crystallization of water at a temperature of 0C, 34 kJ of heat is released. Determine the mass of the formed ice. (Specific heat of crystallization of ice 3.4 105J / kg).
R1 = 240 ohms.
U = 220 V.
The strength of the current I is directly proportional to the voltage U and inversely proportional to the resistance R: I = U / R.
When connecting the conductors in series: R = R1 + R1 = 2 * R1.
I = U / 2 * R1.
I = 220 V / 2 * 240 Ohm = 0.46 A.
Answer: the current strength in the bulbs is I = 0.46 A.
t = 0 ° C.
Q = 34 kJ = 34000 J.
λ = 3.4 * 105 J / kg.
The amount of heat Q, which is released during ice crystallization, is determined by the formula: Q = λ * m.
m = Q / λ.
m = 34000 J / 3.4 * 105 J / kg = 0.1 kg.
Answer: m = 0.1 kg of ice crystallized.
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