Ask a junior high school science question, urgently! Thank you 10

Both the voltmeter and the ammeter are directly connected in series in the circuit, and the voltmeter cannot be directly connected in the circuit or it will not light up (I don't know if yours is like this,) If it is really connected in series and can be lit, you can say how much resistance is the voltmeter, voltmeter.

on the voltage to get most of the voltage, the voltage on the bulb is too small, so the ammeter has an indication and the bulb glows dimly, again.

Because the sliding rheostat is connected in parallel with the bulb, the voltage on the sliding rheostat is the same as the voltage on the bulb, and the voltage of the sliding rheostat is much smaller than that of the voltmeter.

Unchanged (indication is not zero) and less than 6V).

I don't understand that your voltmeter is placed in**ah。。。 Both ends of the power supply? That's right ...

I'm going to follow your description, I don't know, right.

This is a series circuit, a voltmeter in series, in which the closing switch is very large because of its internal resistance, there is a weak current, and the bulb emits a weak light.

Adjust the sliding rheostat No matter how it is adjusted, except for the voltmeter, the resistance of other parts is very small, so the voltmeter is the voltage at both ends of the power supply, and the other parts of the series circuit will also have a small partial voltage, so the indication is less than 6V

You didn't say in the question stem that the power supply should be 6V.

There are too many resistors in the voltmeter.

The resistance of the point pressure gauge is much greater than that of other electrical components, and it is divided into most voltages.

The small bulb is divided into a small part of the voltage and is slightly bright.

Because of the resistance of the voltmeter, the current in the circuit is very small.

The slip resistance has very little effect on the voltmeter indication and cannot be observed.

The resistance of the voltmeter is too large, resulting in too small the current in the circuit, so the bulb is dark, and the sliding plate of the rheostat is arbitrarily sliding, and the voltage representation number remains unchanged (the indication is not zero) and is less than 6V, because the series voltage divider is less than the power supply voltage.

Choose a because the coal and oil in b come from the remains of animals and plants in ancient times, and plants rely on photosynthesis, and animals live by eating plants, so their energy comes from solar energy, and c is the same reason, the water in d evaporates due to sunlight radiation, and then falls into rain, which also comes from solar energy, and the wind is formed by the atmospheric pressure difference formed by sunlight heating the air, or solar energy.

cf=g+p0s

Because the mercury column in the tube is supported by atmospheric pressure, it does not need to be lifted by force.

Taking the glass tube as the object of analysis, the vertical direction of the glass tube is only affected by the downward pressure of the atmosphere on the top of the tube, the gravity of the tube, and the tensile force of man.

Although the mercury is in the tube, there is no force on the tube in the vertical direction, and the three forces are balanced, so f=g+p0s

c1.Sucrose is soluble in water; 2.Alcohol is volatile4It is a physical property that apples have a sour taste.

Solubility Physics.

Volatile Physics.

Combustible chemistry.

Sour biological.

Acidic chemistry. Chemistry.

Just calculate according to the proportions!

m = diameter of the sun

Get the diameter of the sun.

m/ m==

Yin, combustion, light blue blind liter, hydrogen. Small, oxygen.

Leakage Returning to Consciousness m =

1.After direct current is applied in the water, a large gas is produced at the cathode, and this gas is approached with a lit match, and it is found that it burns, producing a pale blue flame. This gas is H2.

The gas produced at the other pole is smaller, and the gas produced by the limb can cause the sparkled strip to rekindle carefully, indicating that the gas is O2.

2.Talking about the conversion of rents and respects:

Answer the confession in turn: negative, combustion, high liquid selling blue, hydrogen, small gas, oxygen, and Qi teasing.

If the solution contains copper chloride, copper chloride can be replaced with iron powder to form copper and ferrous chloride.

Filtrate refers to a solution in which the remaining iron powder is filtered out.

d ferrous chloride.

cuo+2hcl=cucl2+h2o fe+2hcl=fecl2+h2

fe+cucl2=fecl2+cu

There is a surplus of iron powder, which means that the hydrochloric acid is completely reacted, the copper is completely replaced, and there is no CuCl2 in the solution.

Filtrate": The liquid remaining after filtration.

Iron powder has a residual note, all the reactions in the mixture have occurred, and there are 1Iron and hydrochloric acid 2Copper oxide and hydrochloric acid, 3Iron and copper chloride, at this time there is an excess of iron leftover. Then write all the equations and you can find that the solute is only ferrous chloride.

Filtrate refers to the solution after filtering the remaining iron powder, copper chloride and hydrochloric acid do not react, and it is not copper oxide. Because there is iron powder left, the hydrochloric acid is not enough A wrong Iron and hydrochloric acid react to form ferrous chloride So C is wrong D right.

Iron reacts first over copper oxide. Even if a very small amount of copper oxide is involved in the reaction, the resulting copper chloride will still be replaced by iron, resulting in elemental copper and ferric chloride, so copper chloride must not be present, and dilute hydrochloric acid and ferric chloride are even less likely to be there, because there is too much iron.

1. Plains and depressions.

2、c3、b

4. There is no atmosphere.

5. Meteor meteorite.

6. In the year when sunspot activity is at its highest, magnetic storms are frequent.

7. When the temperature rises, the liquid in the thermometer drops.

One circle and one minute, that is, ask a few minutes a day) 9, B10, measure from the cover, the thickness of the cover and the inside are different; Only 10 pages are measured, which is too little.

The thickness of the paper is h=l 10, and there are only 5 sheets of 10 pages.

11, D12, Science**.

13, cm 58

14. Make the mercury column in the glass tube drop to 35 times.

15. The temperature of the water (thermometer), the quality of the water (balance), and the volume of water (graduated cylinder).

2. D4. Because the moon is a vacuum, there is no medium to transmit sound.

5 minutes. Let the resistance value of each section be r

Series resistance: 2r

Series power: U square 2r

Parallel resistance: the reciprocal of (1 r+1 r), i.e. r2 parallel power: u square (r 2).

The ratio is equal to 1 4