问题
填空题
一盏白炽灯,没有通电时,灯丝的电阻______零(填“等于”或“不等于”),白炽灯正常发光时电阻为R1,不发光时的电阻为R2,则R1与R2的大小关系是:R1______R2.
答案
导体的电阻与电压电流没有关系,当电路中没有电流时,导体仍有电阻.白炽灯的灯丝在正常发光和不发光时,材料、长度、横截面积不变,但白炽灯正常发光时温度比不发光时高,所以电阻大.
故答案:不等于、大于.
一盏白炽灯,没有通电时,灯丝的电阻______零(填“等于”或“不等于”),白炽灯正常发光时电阻为R1,不发光时的电阻为R2,则R1与R2的大小关系是:R1______R2.
导体的电阻与电压电流没有关系,当电路中没有电流时,导体仍有电阻.白炽灯的灯丝在正常发光和不发光时,材料、长度、横截面积不变,但白炽灯正常发光时温度比不发光时高,所以电阻大.
故答案:不等于、大于.
完形填空。 | |||
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