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Date Submitted: 03/13/2014 04:37 AM
Suva Grammar School
Department of Mathematics / Physics
Form 7 Physics Assignment 1, Term 2 – 2004
1. A satellite is orbiting the earth in a circular orbit. Use Newton’s laws to derive the expressions for velocity ( v ) and period ( T ) of motion of the satellite in terms of M and r. (2)
2. In a nichrome wire, electrons move with a drift velocity of 0.08 mm/s through a cross-sectional area of 7 mm2. There are 1028 electrons in each m3 of wire.
Calculate the size of the current.
Determine the current density in the wire.
( electronic charge, e = 1.602 10-19 C ) (3)
3. A galvanometer reads 1 mA at full-scale deflection (fsd) and has an internal resistance of 120 (. This is to be converted to an ammeter to read up to 6 A at full – scale.
Draw a circuit diagram to show the conversion.
Calculate the value of the resistance needed for this conversion. (3)
4. A galvanometer reads 5 mA at full-scale deflection (fsd) and has an internal resistance of 90 (. This is to be converted to a voltmeter to read up to 10 V at full – scale.
Draw a circuit diagram to show the conversion.
Calculate the value of the resistance needed for this conversion. (3)
9 V
5. In the multi-loop circuit shown, find:
the current in R. E 2.5 A
the value of R.
the unknown emf (E).
1.5 A
(3)
6. A copper wire of length 3 m and circular cross-section, of radius, r = 1.2 mm. The resistivity of the given wire is 1.7 10-8 (m.
Calculate the resistance of the wire.
What current will flow if a potential difference of 12 V is applied? (3)
7. The circuit below shows a multi – loop circuit.
a 12 V 6 ( b
I1
4 ( 8 V
d c
I3
I2
3 (
e f
Using Kirchoff’s laws;
Write an equation relating the currents.
Write voltage equations for the loops:
(I) abcda (II) dcfed
Calculate the values of the...