Physics Practicals 2

Question 1

Resistance of lamp changing as p.d. Increases

Answer 1

1. Connect circuit as in diagram (battery, variable resistor, bulb, voltmeter, ammeter, switch)
2. Set power supply to 6 V & switch on.
3. Record readings on ammeter & voltmeter & switch off again.
4. Change p.d. across the lamp & repeat for other p.d
5. Switch direction of the power supply by swapping terminals for the wires connecting the
   circuit to power supply. Repeat for other p.d.
6. Replace lamp with resistor.
7. Set power supply to 6 V & Record the readings on ammeter & voltmeter for different p.d.

Question 2

Test parallel & series circuits using resistance & lamps

Answer 2

1. Connect series circuit shown in diagram
2. Set the power supply to 6V & switch on. Record the readings on ammeters & voltmeters.
3. Connect parallel circuit shown in diagram .Repeat step 2.
4. Repeat steps 1-3 using resistors instead of filament lamps.

Question 3

Densities of irregular solids

Answer 3

1. top pan balance to find mass of solid
2. Stand displacement can on bench with its spout over edge of sink.
3. Fill can with water until water starts to come out of spout.
4. Hold measuring cylinder under spout & drop solid into can.
5. If the object floats, push it down until all of it is under water.
6. Stand measuring cylinder on bench & read volume of water collected->same as volume of object.
7. Calculate density using 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 = 𝑚𝑎𝑠𝑠 ÷ 𝑣𝑜𝑙𝑢𝑚𝑒

Question 4

Densities of regular solids

Answer 4

1.measure mass-> top pan balance.
2. Use ruler or Vernier callipers, find height, width, length of block.
3. calculate volume using 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝑙𝑒𝑛𝑔𝑡ℎ × 𝑤𝑖𝑑𝑡ℎ × ℎ𝑒𝑖𝑔ℎ𝑡
4. calculate density using𝑑𝑒𝑛𝑠𝑖𝑡𝑦 = 𝑚𝑎𝑠𝑠 ÷ 𝑣𝑜𝑙𝑢𝑚𝑒

Question 5

Densities of liquids

Answer 5

1. measure mass of empty beaker -> top pan balance.
2. measuring cylinder measure 50 cm3 of liquid & pour in beaker.
3. Record mass of beaker,liquid & calculate mass of liquid by subtracting mass of
   empty beaker.
   Calculate the density using the formula 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 = 𝑚𝑎𝑠𝑠 ÷ 𝑣𝑜𝑙𝑢𝑚𝑒

Question 6

Water-> specific heat capacity

Answer 6

1.Put polystyrene cup in beaker onto balance & zero the balance.
2. fill cup to top with water & write mass of water.
3.put thermometer in water & support it using tripod.
4. Put 12 V electric immersion heater
into water, making sure heating element is below water level.
5. Connect immersion heater to joulemeter (or use voltmeter, ammeter & stopwatch).
6. Record temperature of water & switch on immersion heater.
7. Stir water using thermometer.
8. After 5 minutes, record temperature of water again & write reading on joulemeter (or ammeter & voltmeter).
9. Calculate specific heat capacity of water->
𝑐ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑡ℎ𝑒𝑟𝑚𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦
𝑠𝑝𝑒𝑐𝑖𝑓𝑖𝑐 ℎ𝑒𝑎𝑡 𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦 =
𝑚𝑎𝑠𝑠 × 𝑐ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑡𝑒𝑚𝑝𝑒𝑟𝑎𝑡𝑢𝑟𝑒
10. Repeat 3x & calculate mean for specific heat capacity of water.

Question 7

Water-> heating graph

Answer 7

1.Put boiling tube full of crushed ice into beaker.
2. Put thermometer in ice & note
temperature.
3. Put beaker on tripod & gauze. 4. Pour hot water from kettle into beaker.
4. Keep water warm using Bunsen burner.
5. Measure temperature of ice/water in boiling tube every 30s ->Note time when ice finishes melting.

Question 8

Extension of a spring

Answer 8

1. Set up apparatus shown in diagram.
2. Measure length of spring with no masses hanging on it & write it
3. Hang 100g mass on spring & Record length of spring & calculate extension:
   extension = stretched length — original length
4. Repeat step 3 until you found extension of spring for 10 different masses. Each mass
   puts downward force of 1N on spring.