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Anonymous users2024-02-071. Among the following statements about whether the ammeter and voltmeter can be directly connected to the two poles of the power supply, what do you think is correct
A ammeter is OK, voltmeter is not OK b Both types of meters are OK.
c The ammeter is not OK, the voltmeter can be d Both meters are not allowed.
2. A "220V 40W" bulb, connect it to a 230V circuit, and the power consumed by the bulb ( ).
A greater than 40w b less than 40w c equals 40w d cannot be determined.
3. The two lamps A and B in series in the circuit, if the A lamp is brighter than the B lamp, then the current i A through the A lamp and the current i B through the B lamp are compared with ( ).
a i a = i b i a i i b c i a i b d the condition is insufficient to judge.
4. A fixed value resistor marked with a resistance value of 20, if the passing current is, then the voltage at both ends of the resistance is ( ).
A 40v b 10v c d condition is insufficient.
5. As shown in the figure on the right, after the switch S is closed, the voltage measured by the voltmeter is ( ).
A Voltage at both ends of lamp L1 BVoltage at both ends of the lamp L2.
c The total voltage of lamps L1 and L2 DNone of the above statements are correct.
6. If a conductor is connected to a circuit, if the voltage applied to both ends of it is doubled, the following statement is correct about the resistance of the conductor and the current passing through it
a Resistance and current remain the same b Resistance remains the same and the current doubles.
c The current does not change, and the resistance is doubled, and the resistance and current are doubled.
7. The three lights of A, B and C are marked with the words "110V 20W", "220V 10W", "36V 35W" respectively, and the three lights are all shining normally, compare their brightness ( ).
A, A lights are the brightest, B, B lights are the brightest, C, C lights are the brightest, D, all three are the same.
8. In the circuit shown in the figure on the right, the power supply voltage is 10 volts and remains unchanged, the resistance r1 = 10 ohms, and the maximum resistance of the sliding rheostat is 30 ohms
a）,0~6v （b）,0~6v
c）,4~10v （d）,4~6v
9. A student did an electrical experiment, the circuit is shown in Figure 3, after the switch is closed, the small bulb shines, and the two meters have an indicator, during the experiment, the lamp suddenly goes out, the voltage indicates that the number increases, and the ammeter is almost zero. Determine the possible cause of this phenomenon ( ).
a, the bulb is short-circuited b, the switch is disconnected c, the filament is burned d, and the sliding rheostat is burned out.
10. The voltage at each end of the decorative small lantern is not allowed to exceed 10V, and ask how many lamps must be connected in series at least before the home circuit can be used as the power supply ( ).
A 20, B 21, C 22, D 23.
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Anonymous users2024-02-0621.(10 points) The circuit connection is shown in Figure 7, and the light bulb L is marked with the word "12V". After 5min of power-on, the bulb L emits light normally, and the current is expressed as at least 5 unknown physical quantities according to these known conditions, through analysis and calculation.
It is required to write down the values and units of physical quantities clearly).
1) When K, K1 and K2 are closed, the A1 indication of the ammeter is, the small bulb L happens to emit light normally, find the power supply voltage, the rated voltage of the small bulb and the A2 indicator?
2) When K is closed and K1 and K2 are disconnected, what is the actual power of the small bulb when the indication of ammeter A2 is?
3) What is the power rating of a small bulb?
23.(8 points) As shown in Figure 9, the power supply voltage remains unchanged. When the sliding blade p of the sliding rheostat R1 is located at the B terminal, the indication of the ammeter is that the ratio of the resistance R to the voltage at both ends of the sliding rheostat R1 is 3:
5. At this time, the power consumed by R is known that the specification of the lamp is "10V 10W", and the filament resistance does not change with temperature. Seeking:
1) The resistance value of R, the maximum resistance value of the sliding rheostat R1.
2) The possible range of indication changes in the ammeter.
3) When the sliding rheostat slide is in the position, the power consumed by the circuit is the smallest, and the power of the bulb at this time is found.
21.Current rating.
Bulb resistance 40
The electric power of the bulb is 1080J
Resistance value 50
Resistive power. The resistor consumes 864J of electrical energy
The total work done by the current is 1944j
22.(1)12v, 12v, 0a (2) (3)
23.(1) 30 , 50 (2) (3) When P slides to the B terminal, the power is the smallest;
Look at my band answers.
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Anonymous users2024-02-05Here I don't know what you want or not! I went to take a look, it seems that there are many types of similar, it's embarrassing, if it's not suitable, I don't know if there's electricity, I've just finished Unit 8, and I'm going to take the exam next week.
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Anonymous users2024-02-04It is not necessary to do many questions, but to focus on the understanding and mastery of knowledge, so as to be able to respond to all changes with the same. Hope it helps.
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Anonymous users2024-02-03You have to answer for yourself and seek truth from facts
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Anonymous users2024-02-02The voltage loaded at both ends of the bulb is equal to the power supply voltage, so the voltage is constant, whereas the bulb resistance is constant, so the brightness of the bulb does not change.
The sliding rheostat slides to the right, causing the total resistance in the circuit to become larger, so the ampere representation number becomes smaller.
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Anonymous users2024-02-01Because it is connected in parallel, the bulb branch is not affected by the sliding rheostat branch, so the brightness does not change.
The sliding resistance of the sliding rheostat to the right becomes larger, and the current becomes smaller by i=u r, so the total current becomes smaller.
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Anonymous users2024-01-31In the junior high school knowledge stage, the resistance of the ampere meter and the wire is ignored, and the bulb is connected in parallel with the other two resistors (the two resistors can be regarded as one), that is, before and after the rheostat slide slides to slide, the voltage at both ends of the bulb does not change, and is always equal to the power supply voltage, so the brightness of the bulb remains unchanged.
When the slide slides to the right, the resistance of the entire circuit increases, while the power supply voltage does not change, so the current decreases and the amperage decreases.
The brightness of the bulb does not change, and the indicator of the ampere meter decreases.
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Anonymous users2024-01-30The brightness of the bulb does not change, because the voltage at both ends of the bulb is always the same, so i bulb = u r bulb.
The indication of the ampere meter becomes smaller, because the resistance RP of the sliding rheostat becomes larger, so the current ir=u (R+RP) through R and Rp becomes smaller, and then the total current is.
I total = i bulb + IR, is a reduction, ,
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