Lv 2589 points

# Irene

• ### current between the plates?

Two metal plates are a distance of 30cm apart in a vacuum.

A current exists between the two plates consisting of electrons moving at a constant speed of 1.5 × 106 ms–1.

At any instant, there is always just one electron travelling between the plates.

What is the current between the plates?

• ### A 0.80 m length of steel wire and a 1.4 m length of brass wire are joined together?

A 0.80 m length of steel wire and a 1.4 m length of brass wire are joined together. The combined wires are suspended from a fixed support and a force of 40N is applied, as shown.

The Young modulus of steel is 2.0 × 1011Pa.

The Young modulus of brass is 1.0 × 1011Pa.

Each wire has a cross-sectional area of 2.4 × 10–6 m2

The wires obey Hooke’s law.

What is the total extension? Ignore the weights of the wires.

• ### Which formula identifies a single substance?

Structural isomerism and stereoisomerism should be considered when answering this question.

Which formula identifies a single substance?

A CH3CHClCH2CHO

B CH3CHCHCH3

C CH2ClCH2CHCl2

D C4H10

What does single substance mean?

• ### Total volume of gas present in the reaction?

10 cm3 of ethane is burned in 45 cm3 of oxygen at a pressure of 101kPa and a temperature of 200 °C. Complete combustion takes place.

What is the total volume of gas present when the reaction is complete, measured under the same conditions?

Thanks a lot.

• ### State the difference in the distances, from each slit to point Y?

How to find it? Thanks

• ### A factory makes a large number of ropes with lengths either 3 m or 5 m. ?

A factory makes a large number of ropes with lengths either 3 m or 5 m. There are four times as many

ropes of length 3 m as there are ropes of length 5 m.

One rope is chosen at random. Find the expectation and variance of its length

The answer for expectation is 3.4 but how to find it?

Thanks

• ### Total distance moved by particle from time t to time (t+100ms)?

A particle in the string oscillates with an amplitude of 13mm. At time t, the particle has zero displacement

How to calculate ‘total distance moved by the particle from time to time (t+100ms)?

• ### Number of proton and neutron?

How to calculate c)?

Thanks

Thanks

• ### Phase different and Intensity?

1)Determine the phase difference between the waves.

How to find it?

2)The intensity of wave Y at point P is I.

Determine, in terms of I, the intensity of wave Z

Thanks

Still thanks

Thanks!

Thank you!

• ### Stationary wave ?

The answer is B but how to solve it?

Could anyone give my some tips to solve this type of question?....

Thank you

• ### What’s the horizontal force exerted by the wall on rod XY?

First, I calculate the length of ZX and I get 0.288675m. I choose Z as pivot and apply the equation clockwise moment equal to anti-clockwise moment which is  0.288675 x F cos 30 = 75(0.5) and I get 150N for the answer. However, the answer is 130N. Anyone knows how to solve it?

Thanks

• ### Relative atomic mass?

Anyone knows how to solve this question?

Thanks

• ### Equilibrium in gas reaction?

At a pressure of 2.00 × 107 Pa, 1.00 moles of nitrogen was mixed with 3.00 moles of hydrogen. The final equilibrium mixture formed contained 0.300mol of ammonia.

Calculate the amounts, in mol, of nitrogen gas and hydrogen gas in the equilibrium mixture.

The answers are 0.850 mol for nitrogen gas and 2.55mol for hydrogen gas but I can't get the asnwer.

This is what I had done:

N2 + 3 H2 <--> 2 NH3

........Initial.....Change......Equilibrium

N2.....1...........+(-0.30)..........0.7 mol

H2.....3..........+3(-0.3).............2.1 mol

NH3...0...........-(-0.3).........     0.3 mol

Are there any mistakes?