4. When some students discussed the phenomenon of heat generated by current passing through a conductor after class, they expressed the following opinions. What do you think is wrong A. When the voltage at both ends of the conductor is constant and the current is constant, the longer the power on time is, the more heat is released B. As long as the resistance of the conductor is large and the power on time is long, more heat will be released C. The process of electric current releasing heat through conductor is the process of electric energy transforming into heat energy D. If the resistance of the conductor is zero, the conductor will not heat no matter how large the current is

4. When some students discussed the phenomenon of heat generated by current passing through a conductor after class, they expressed the following opinions. What do you think is wrong A. When the voltage at both ends of the conductor is constant and the current is constant, the longer the power on time is, the more heat is released B. As long as the resistance of the conductor is large and the power on time is long, more heat will be released C. The process of electric current releasing heat through conductor is the process of electric energy transforming into heat energy D. If the resistance of the conductor is zero, the conductor will not heat no matter how large the current is

4. When some students discussed the phenomenon of heat generated by current passing through a conductor after class, they expressed the following opinions. What you think is wrong is: (b) the analysis is as follows: A. when the voltage at both ends of the conductor is fixed and the current passing through is fixed, the longer the power on time is, the more heat will be released

Physics problems about electricity and heat
For a bulb with the same rated voltage, the higher the rated power is, the smaller the resistance is, and the more heat is generated per unit time. However, according to Joule's law, the greater the resistance is, the more heat is generated per unit time. There seems to be a contradiction between the two. What's the matter?

According to Joule's law, the greater the resistance is, the more heat is generated per unit time. This sentence is wrong, because it is also related to the size of current I. if the current is added, it is correct under certain conditions, q = I ^ 2rt, and the voltage is u, the larger R is, the smaller the current is. Therefore, the change of Q can not be judged only according to the above formula, But q = (U / R) ^ 2rt = u ^ 2T / R, so after conversion, we can judge the change of power when R changes