Top answers

Trend in Melting point going down group 1 elements

Going down group 1 the period number increases. This means the number of shells increases, leading to a decrease in electrostatic attraction between the positive nucleus and outer most electrons. This weaker...
AU
Answered by Amin U. • Chemistry tutor
13833 Views

When a 470 micro farad capacitor is discharged through a fixed resistor R, the pd across it decreases by 80% in 45 s. Calculate the time constant of the circuit

Using the equation V=V 0 e -t/RC where RC is the time constant to be calculated: We know that the pd decreases by 80%, therefore the pd remaining, V is 0.2*V 0 . Putting this into the equation above: 0.2=e -...
PK
Answered by Peter K. • Physics tutor
13930 Views

The first term of an arithmetic series is a and the common difference is d. The 12th term is 66.5 and the 19th term is 98. Write down two equations in a and d then solve these simultaneous equations to find a and d.

The first step is to recall the formula for arithmetic progressions: u(n) = a + (n-1) d We can then put all the information given in the question into this so u(12) = 66.5 = a + 11d and u(19) = 98 = a + 18d ...
EW
Answered by Eleanor W. • Maths tutor
7693 Views

A curve has equation (x+y)^2=x*y^2, find the gradient of the curve at a point where x=1

Differentiating left hand side: 2(x+y)(1+dy/dx) from the chain rule 2. Differentiating right hand side: y 2 +2xy(dy/dx) from the product rule 3. Equating sides and taking out factors of dy/dx to rearrange fo...
PK
Answered by Peter K. • Maths tutor
4744 Views

How do I write an Oxbridge personal statement?

For this I would advise three key points. (1) Remember you're applying to study a subject not , for a career. At Oxbridge there is a special emphasis on this and the people responsbile for admissions will be...
SP
2176 Views