MYTUTOR SUBJECT ANSWERS

627 views

A lamp has a rating of 18V 9W. How much energy is transferred to the bulb in 5 minutes? Calculate the current through it when connected to a 18V supply.

The first question comes from the realisation that the power rating, "9W" represents 9 joules being supplied every second and so can be written as 9J/s and so in 5 minutes (or 300 seconds) the energy supplied is:
9J/s * 300s = 2700J 

The second part comes from the equation P=IV and we already have numbers for power and voltage:
9 = 18 * I 
I = 9/18 = 0.5Amps

Alexander N. GCSE Physics tutor, IB Physics tutor

2 years ago

Answered by Alexander, a GCSE Physics tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

163 SUBJECT SPECIALISTS

£22 /hr

Joshua T.

Degree: Chemistry PhD (Doctorate) - Bristol University

Subjects offered:Physics, Chemistry

Physics
Chemistry

“Chemistry PhD student at the University of Bristol, with a masters degree in chemistry from the University of Oxford. Available to teach Chemistry and Physics”

£22 /hr

Joe C.

Degree: General Engineering (Masters) - Durham University

Subjects offered:Physics, Science+ 2 more

Physics
Science
Maths
Computing

“Masters student at Durham University, ready to help you excel at Maths and Science ”

PremiumLorenzo C. GCSE Biology tutor, A Level Biology tutor, GCSE Chemistry ...
£24 /hr

Lorenzo C.

Degree: Biomedical Sciences with Honours in Infectious Diseases (Bachelors) - Edinburgh University

Subjects offered:Physics, Chemistry+ 1 more

Physics
Chemistry
Biology

“5th in the World at International A-Level Biology Over two years experience in tutoring!”

About the author

Alexander N.

Currently unavailable: for regular students

Degree: Physics (Bachelors) - Durham University

Subjects offered:Physics

Physics

“About me:I am a physics student, studying at Durham University and I have always loved teaching people. I initially started it as my favourite way to learn and study. I would try to teach anything I had learnt to a friend, my parents...”

MyTutor guarantee

You may also like...

Posts by Alexander

A lamp has a rating of 18V 9W. How much energy is transferred to the bulb in 5 minutes? Calculate the current through it when connected to a 18V supply.

On a see-saw Mary, weight 600N balances John, weight 200N when she sits 1.5m away from the pivot. How far from the pivot is John?

Resistors of 5 ohms and 10 ohms are connected in series with a battery supplying 3 volts. What is the total resistance ? And calculate the current in the circuit.

The loudspeaker produces a sound wave with a frequency of 850 hertz and a wavelength of 0.4 metres. Calculate the speed of this sound wave. Give the unit

Other GCSE Physics questions

Define the term ultrasound wave

A rollercoaster carriage of mass 100kg has 45kJ of Kinetic Energy at the lowest point of its ride. Ignoring air resistance and friction between the wheels and the tracks, what is the maximum height above this point it could reach? [Take g as 10m/s/s)

Whats the difference between speed and velocity?

Which state can a substance NOT be in if heat transfer through convection is occurring?

View GCSE Physics tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok