Exam Qu Flashcards
Define the term power?
Rate of energy transferred
Explain how a step down transformer work?
Decreases voltage
Current in primary coil produces a mag field
Due to the current changing current the mag field changes
The field lines interact with the secondary coil inducing a voltage
Describe how the oscilloscope is used to measure the time period of an ultrasound wave?
Adjust the time base to display one cycle
Then evaluate the number of squares for a full cycle
Multiply number of squares for full cycle by time base
What is the role of the control rod?
Absorb Excess Neutrons
What is the role of a moderator?
Reduce the speed of neutrons so they can cause fission
Describe the roll of shielding around a nuclear reactor?
Decreases the risk of radiation escaping by absorbing the neutrons
How does CMBR support the big bang theory?
Appears to be the same everywhere.
Implies that all parts of the universe were in contact suggesting the wavelength has increased as universe expands
How does Red Shift support the big bang theory?
Red shift of GALAXIES
Further the galaxy is from earth the greater the redshift.
Larger redshift suggests a faster movement of galaxies away
Moving away suggests and expansion from a single point
Define the term Specific Heat Capacity?
Energy to change temperature by 1 degree per kilogram of mass
Define elastic behaviour?
Idea that material return to original shape when the force/load is removed
Describe how a teacher could measure the count rate from a radioactive source and correct the count rate for background radiation?
Use a Geiger muller tube (GM tube)
Remove the source from the room
Measure count rate several times and take a mean
Subtract the total count rate from the background
Explain the path of the ray of light as it travels through the optical fibre?
Total Internal Reflection Occurs
because angle of incidence is greater than the critical angle and the core has a higher refractive index than air
Why would an LED flash on and off in a circuit with an a.c current?
Due to the current changing direction
LED only allows the current in one direction so it won’t light up when current is in reverse direction
Compare the arrangement of a liquid and solid particles?
Solid is regular arrangement
Liquid is irregular arrangement
Both are closely packed
Explain what happens to the magnitude of force of a block moves closer to point A than point B?
Force of A will Increase
Due to the distance from point A decreases so the clockwise (or anti) movement increase
Anti-clockwise moment will increase to balance
Explain why an object may not experience Newton’s third law?
Forces may act on the same body
Forces may not have the same origin
What direction do circles move when the current moves in and out of the page?
Into - Anticlockwise
Out - Clockwise
Explain why two wires in a downward direction would move towards one another?
Both wires have a magnetic field around them
Each wire has a current in a magnetic field
Each wire will experience a force which will both be the same size in opposite directions
