paper 1 aqa physics required practicals Flashcards
(15 cards)
What is the definition of specific heat capacity?
-The amount of energy required to raise the temperature of 1 kg of a substance by 1°C.
Why do we use an insulator around the metal block?
-To reduce energy loss to the surroundings and improve reliability.
What are common sources of error in the specific heat capacity practical?
-Heat loss to surroundings, inaccurate temperature readings, and poor thermal contact between the heater and block.
How can you reduce heat loss in this experiment?
-Use insulating material, place a lid on the block, and ensure good contact between the heater and metal.
Why is it important to wait a few minutes after switching off the heater before recording the final temperature?
-To allow heat to distribute evenly throughout the block for accurate temperature measurement.
Describe how you would carry out an experiment to determine the specific heat capacity of a metal block.
-Measure the mass of the metal block using a balance.
-Insert an electric heater and thermometer into the two holes of the metal block.
-Wrap the block in insulating material to reduce heat loss to the surroundings.
-Connect the heater to a power supply, ammeter, and voltmeter to measure current and voltage.
-Record the initial temperature of the block, switch on the power supply, and start the stopwatch.
-After a set time (e.g. 10 minutes), switch off the heater and record the final temperature.
Calculate energy transferred using E = V × I × t.
What is the dependent variable in this experiment? ( thermal insulator )
-The temperature change
How do you reduce energy transfer in this experiment?
-Use a lid and wrap the container in insulating material.
Why is it important to use a lid in this practical?
-To reduce energy transfer via evaporation and convection.
Why is the temperature measured every minute?
-To observe how quickly the temperature drops and calculate the rate of heat loss.
Why should you repeat the experiment for different materials or thicknesses?
- To compare results and improve reliability.
Describe how you would investigate the effectiveness of different insulating materials on the rate of heat loss. (6 marks)
-Fill a small container or beaker with hot water and measure the initial temperature using a thermometer.
-Wrap the container in the first chosen insulating material and place a lid on top to reduce heat loss.
-Start a stopwatch and record the temperature at regular intervals (e.g. every minute for 10 minutes).
-Repeat the experiment with different insulating materials, keeping the volume of water and starting temperature the same.
-Record and compare the rate of temperature decrease for each material to determine which is the best insulator.
-Conclude which material reduces heat loss most effectively by identifying the one with the slowest temperature drop.
Describe how you would investigate the I–V characteristics of a component such as a resistor, filament bulb, or diode. (6 marks)
-Set up a circuit with the component, a variable resistor, a power supply, an ammeter in series, and a voltmeter in parallel across the component.
-Adjust the variable resistor to change the potential difference and record the current and voltage readings.
-Take multiple readings by varying the resistance to get a wide range of values for current and potential difference.
-Reverse the power supply connections to obtain negative values for current and voltage (where applicable).
-Repeat the process for each component: resistor, filament bulb, and diode, using the same method.
-Plot I–V graphs for each component and analyse the shape of the graph to determine the relationship.
Describe how you would investigate how the resistance of a wire depends on its length. (6 marks)
-Set up a circuit with a wire secured to a ruler, a power supply, an ammeter in series, and a voltmeter across the test wire.
-Attach one crocodile clip at 0 cm and the other at a specific length (e.g. 10 cm) to complete the circuit.
-Record the voltage (V) and current (I) for that length, then calculate resistance using R = V / I.
-Repeat the steps for different lengths of wire
-Switch off the power supply between readings to reduce wire heating and keep resistance accurate.
-Plot a graph of resistance against length and describe the relationship (e.g., directly proportional).
Describe how you would determine the density of a regular solid, an irregular solid, and a liquid. (6 marks)
-Regular Solid: Measure the object’s length, width, and height using a ruler, calculate its volume using volume = length × width × height, and measure its mass using a digital balance. ✅
-Calculate Density (Regular): Use the formula density = mass ÷ volume and ensure units are consistent (e.g. grams to kilograms or cm³ to m³ if needed). ✅
-Irregular Solid: Measure the mass using a digital balance. Submerge the object in a displacement can or measuring cylinder and measure the volume of water displaced to find its volume. ✅
-Calculate Density (Irregular): Use the formula density = mass ÷ volume with the displaced volume and measured mass. ✅
-Liquid: Place an empty measuring cylinder on a balance and zero it. Pour in the liquid and record the mass, then use the volume reading from the cylinder. ✅
-Calculate Density (Liquid): Apply density = mass ÷ volume using the measured liquid mass and volume. ✅
