Numerade

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c. A glass cube is held in contact with a liquid and a light ray is directed at a vertical face of the cube. The angle of incidence at the vertical face is \( 39^{\circ} \) and the angle of refraction is \( 25^{\circ} \) as shown in the diagram. The light ray is totally internally reflected for the first time at X. Complete the diagram to show the path of the ray beyond \( X \) to the air and calculate the critical angle for the glass-liquid boundary. d. Opals and diamonds are transparent stones used in jewellery. Jewellers shape the stones so that light is reflected inside. Compare the critical angles of opal and diamond and explain which stone would appear to sparkle more. The refractive index of opal is about 1.5 The refractive index of diamond is about 2.4 .

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Eduard Sanchez

Numerade educator

A sound wave has a speed of 3.3 x 102 m/s and a frequency of 4.33 x 104 Hz. What is the wavelength of the wave? b. A ray of light enters a glass block of refractive index 1.53 making an angle of 15° with the normal before entering the block. Calculate the angle it makes with the normal after it enters the glass block.

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a. A rescue vehicle is travelling at a constant velocity of 25 m·s–1 and sounds its siren at a frequency of 460 Hz. (i).Determine the frequency of the siren as heard by the driver of a stationary car as the rescue vehicle approaches her. (ii).Determine the frequency of the siren heard by the driver of the car as the rescue vehicle moves away from her. b. A jet plane flying at 320 km·h–1 flies over an airport. A stationary observer at the airport hears the sound of the jet engines at a frequency of 30 kHz as the plane flies away. Determine the frequency of the sound of the plane’s engines when the plane is stationary on the runway. QUESTION TWO a. A train travelling at a constant speed sounds its whistle at a frequency of 530 Hz. A man standing at the side of the railway track hears the sound of the whistle at a frequency of 510 Hz. (i). Is the train moving towards or away from the man? Explain. (ii) Calculate the speed of the train. (iii).If the train were travelling faster than the speed calculated in Question 2ii, will the frequency of the whistle as heard by the man be larger or smaller than 510 Hz? b. Explain the meaning of the following terms: (i) Doppler flow meter (ii) blue shift.

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Vishal Gupta

Numerade educator

9.2 In the diagram below, a battery with an emf of 6 V and an internal resistance of 2 ?, is connected to three resistors P, Q and R. A voltmeter V is connected across the battery. The ammeter A has a negligible resistance. 9.2.1 Calculate the ammeter reading when switch S is closed. (5) The switch S is now open. 9.2.2 Will the ammeter reading in QUESTION 11.2.1 INCREASE, DECREASE or REMAIN THE SAME? Give a reason for the answer. (2) 9.2.3 How will the voltmeter reading now compare with the voltmeter reading when the switch is closed? Choose from INCREASE, DECREASE or REMAIN THE SAME. (1) 9.2.4 Explain the answer to QUESTION 9.2.3. (3) [15]

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INSTANT ANSWER

sheet alongside. 8.1.2 Draw the line of best fit through the plotted points. Ensure that the line cuts both axes. (2) Use information in the graph to answer QUESTIONS 8.1.3 and 8.1.4. 8.1.3 Write down the value of the emf (1) of the battery. 8.1.4 Determine the internal resistance of the battery. (3) 8.2 The circuit diagram shows a battery with an emf (c) of 60 V and an unknown internal resistance \( r \), connected to three resistors. A voltmeter connected across the \( 8 \Omega \) resistor reads \( 21,84 \mathrm{~V} \). Calculate the: 8.2.1 Current in the \( 8 \Omega \) resistor (3) 8.2.2 Equivalent resistance of the resistors in parallel (2) 8.2.3 Internal resistance \( r \) of the battery (4) 8.2 .4 Heat dissipated in the external circuit in 0.2 seconds (3) [20]

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Formula for internal resistor

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Fomurla for emf of a battery

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battery of an unknown emf and an internal resistance of 0,5 Q is connected to three resistors, a high-resistance voltmeter and an ammeter of negligible resistance, as shown. The reading on the ammeter is 0,2 A. 5.1 Calculate the: 5.1.1 Reading on the voltmeter Total current supplied by the battery Emf of the battery How would the voltmeter reading change if the 2 Q resistor is removed? Write down INCREASE, DECREASE or REMAIN THE SAME. Explain the answer.

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(3) (4) (5) (3) [15] 6.1.1 Calculate the resistance of the 4 W bulb. 6.1.2 How will the equivalent resistance of the circuit change if the 6 W bulb burns out? Write down only INCREASES, DECREASES or NO CHANGE. 6.1.3 How will the power dissipated by the 10 W bulb change if the 6 W bulb burns out? Write down only INCREASES, DECREASES or NO CHANGE. Give a reason for the answer. Section treak (inest page)

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[15] QUESTION 10 10.1.1 State Ohm's law in words. (2) The reading on ammeter \( A_{2} \) is \( 0,6 \mathrm{~A} \) when switch S is closed. Calculate the: 10.1.2 Reading on voltmeter \( \mathrm{V}_{1} \) (3) 10.1.3 Current through the \( 6 \Omega \) resistor (2) 10.1.4 Reading on voltmeter \( \mathrm{V}_{2} \) (2) 10.1.5 \( \mathrm{Emf}(\mathrm{t}) \) of the battery (3) 10.1.6 Energy dissipated as heat inside the battery if the current flows in the circuit for 15 s (3)

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Hangwe K.