Biology; Chemistry; Physics: Post your doubts here!

[Maganius]

but how? how are the strengths and weight related?
as in the weight will increase if it attracts iron bar ? is that so?

We're using newton bar so that when we pull EM apart ( magnet and steel bar ) how much force is needed to separate em both. We'll repeat the same process with another magnet and jot down the force it used to separate itself from iron bar. We'll compare both the forces and the one with larger force would be a stronger magnet.

 

[funky brat]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s13_qp_42.pdf
Q3 anyone?

You just need to measure the volume so take a measuring cylinder with a spout, fill with water not fully to allow for displacement. Place another measuring cylin. at the bottom of spout. Immerse the stopper, measure the amount of water displaced. Read the vloume on the 2nd cylinder. This is the vloume of stopper. In next part, you may write, place the stopper gently to avoid splashing.

 

[Maganius]

p

put some water in displacemnet can just below its spout.place a measuring cylindaer below the spout .carefully place the stopper in the displacement can.some amount of water falls into the cylinder.measure hat amount.that will be its volume

Thanks

 

[Maganius]

You just need to measure the volume so take a measuring cylinder with a spout, fill with water not fully to allow for displacement. Place another measuring cylin. at the bottom of spout. Immerse the stopper, measure the amount of water displaced. Read the vloume on the 2nd cylinder. This is the vloume of stopper. In next part, you may write, place the stopper gently to avoid splashing.

It's same like measuring the volume of a rock or any other object right? We've to use V=V2 - V1, right?

 

[DaniyalK]

I still didn't get the answer to my question that one division on main scale and vernier scale equals to what? :/

The main scale gives readings in cm. It has a precision of .1 cm or 1 mm. The number of markings on the vernier after which 2 points coincide are added as 0.1 mm. For example the main scale may read 3.1cm and the points of the vernier and main scale coincide after 4 markings so the answer is 31 mm + 0.4 mm = 31.4 mm

 

[mohammad ahmed]

n

Thanks

np bro. hope allah grants us success in tomoroows paper

 

[funky brat]

Why does the reflection of sound changes its magnitude but not wavelength ?

Sound is caused by vibration which is due to energy, so reflection causes energy loss, hence magnitude of sound decreases. But the speed of sound remains the same as long as the media are same, also frequency is determined by the source, so when these two are unaffceted, wavelnegth does not change.

 

[Maganius]

n


np bro. hope allah grants us success in tomoroows paper

Ameen
Thanks a lot bro ^_^

 

[funky brat]

It's same like measuring the volume of a rock or any other object right? We've to use V=V2 - V1, right?

You can use that here too.

 

[funky brat]

Faizan Muhammmad

 

[Faizan Muhammmad]

There is no relay neuron in knee jerk. It's a monosynaptic reflex meaning only one synpase, between the sensory and motor.

RELAY IS NOT THERE.

Like lizard's tail?
no relay, automatic movement

 

[funky brat]

'initially choose the highest range for the ammeter/voltmeter, then reduce the range for the ammeter so that the deflection is almost full scale'
Explain please. What's full scale deflection?

 

[funky brat]

Like lizard's tail?
no relay, automatic movement

Lol, whatt?

 

[Maganius]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s13_qp_42.pdf
Q4

Btw, how should I attempt such questions?

 

[Faizan Muhammmad]

Lol, whatt?

that pattelar reflex thingy

 

[DaniyalK]

Can somebody explain how to use set squares to avoid parallax error when taking measurements from a ruler?

 

[funky brat]

that pattelar reflex thingy

Dafa karo usey abhi, Physics ki fikar karo.

 

[Mahnoorfatima]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_w12_ms_42.pdf
In question 1 part b ii: Can I write this:
By placing two wooden blocks at the end of the tray then measuring the distance of the traveled wave? :s made it up myself

 

[DaniyalK]

'initially choose the highest range for the ammeter/voltmeter, then reduce the range for the ammeter so that the deflection is almost full scale'
Explain please. What's full scale deflection?

Suppose you're measuring a potential difference of 4V. You start with a voltmeter that can read up to 20v. The needle only moves a little since the magnitude is small compared to the range of the voltmeter. Then you use a 5V voltmeter to measure the same pd, so that the needle almost fully moves to the right. The smaller range gives a more accurate reading.

 

[funky brat]

Can somebody explain how to use set squares to avoid parallax error when taking measurements from a ruler?

Umm yeah do you get this?