IB Physics Final Topic 5

The diagram shows a charged particle as it approaches a pair of charged parallel plates in a vacuum.
Which row describes the horizontal and vertical components of its motion as it travels between the plates? 

• A
• B
• C
• D

A copper wire of cross-sectional area 2.0 mm² carries a current of 10 A.
How many electrons pass through a given cross-section of the wire in one second? 

• 1.0×10¹ 
• 5.0×10⁶ 
• 6.3×10¹⁹ 
• 3.1×10²⁵ 

A battery is marked 9.0 V.
 What does this mean? 

• Each coulomb of charge from the battery supplies 9.0J of electrical energy to the whole circuit. 
• The battery supplies 9.0 J to an external circuit for each coulomb of charge. 
• The potential difference across any component connected to the battery will be 9.0 V. 
• There will always be 9.0 V across the battery terminals. 

The resistance of a metal cube is measured by placing it between two parallel plates, as shown.
The cube has volume V and is made of a material with resistivity ρ. The connections to the cube have negligible resistance.
Which expression gives the electrical resistance of the metal cube between X and Y? 

• A
• B
• C
• D

 The diagram shows part of a current-carrying circuit. The ammeter has negligible internal resistance.
What is the reading on the ammeter? 

• 0.7 A
• 1.3 A
• 1.5 A
• 1.7 A

Four resistors of equal value are connected as shown.
How will the powers to the resistors change when resistor W is removed? 

• The powers to X, Y and Z will all increase. 
• The power to X will decrease and the powers to Y and Z will increase. 
• The power to X will increase and the powers to Y and Z will decrease. 
• The power to X will increase and the powers to Y and Z will remain unaltered. 

In the circuit shown, XY is a length L of uniform resistance wire. R₁ and R₂ are unknown resistors. J is a sliding contact that joins the junction of R₁ and R₂ to points on XY through a small signal lamp S. 
To determine the ratio V₁/V₂ of the potential differences across R₁ and R₂, a point is found on XY at which the lamp is off. This point is at a distance x from X. What is the value of the ratio V₁/V₂ ? 

• A
• B
• C
• D

Two positive point charges P and Q are held a certain distance apart.
At which point(s) could the electric field strength, due to the charges, be zero? 

• X only
• Y only
• Z only
• X and Z only

The ampere is defined in terms of 

• the force between a magnet and a coil carrying a current. 
• the force between two long current carrying wires. 
• the amount of charge that passes any cross-sectional area of a wire in unit time. 
• the number of electrons that pass any cross-sectional area of a wire in unit time. 

Which one of the following shows a correct circuit, using ideal voltmeters and ammeters, for measuring the I-V characteristic of a filament lamp? 

• A
• B
• C
• D