EXAMSHARE

Western Delta University, Oghara Delta State

department of physics with electronics
college of natural and applied sciences
western delta university

second semester examination 2022/2023 session

PHY102 - Waves and Thermal Physics time: 2hrs

answer question ONE and any other TWO questions from each SECTION

  1. CONSTANTS:

    Specific heat capacity of water: 4.185kj/kg°C

    Velocity of sound in air: 340m/s

    Volume of light in vacuum: 3*108m/s

  2. SECTION A: VIBRATIONS AND WAVES - Answer Question 1 and any other TWO (2)

    1. Question 1

      1. A string vibrates according to the equation y = 0.6m{[(sin π/4 m-1)x][(cos 40πs-1)t]}. What is the amplitude of this wave?
      2. What is the frequency of the wave in (i)
      3. An X-ray has a frequency of 1 x 1018Hz. What is its wavelength?
      4. Ultrasound wave travel in same direction with the particle vibration. True / False.
      5. Increasing the mass of a string decreases the frequency of the pulse passing throught it. True / False
      6. Arrange these electrromagnetic waves in order of increasing wavelength: Visible spectrum, Gamma ray, Radio waves, X-rays.
      7. A wave has a wavelength of 20m and frequency of 100Hz. What is it's wave number?
      8. A 0.5m long thin uniform tube closed at one end is filled with air. Calculate the frequency of the first harmonics where resonance will occur.
      9. What will be the frequency if both ends of the tube are open in question (vii) above?
      10. In a setence interpret this equation: E a A2 sin2 (wt + ø)

    2. Question 2

      1. Give five differences between travelling wave and standing wave
      2. What is the velocity of a wave in a string of legnth 1m and mass of 20g which has tension of 200N in it?

    3. Question 3

      1. Briefly explain why microwave oven is more efficient than conventional oven.
      2. A string fixed at both ends has a fundamental frequency of200Hz. The wave speed on the string is 1000m/s. What is the lenghth of the string?

    4. Question 4

      1. What do you understand by Intensity of a sound?
      2. Write the equation of a travelling wave in a positive x-direction having amplitude of 5m, a wavelength of 20m and frequency of 100Hz.
      3. Show that y = asin(kx - wt) can be written in the form y = asin k(x - vt)

  3. SECTION B: THERMAL PHYSICS - Answer Question 1 and any other TWO (2)

    1. Question 1

      1. _______ is an instrument used to measure gas pressure?
      2. The upper fixed point of an unmarked thermometer can be determined using _______
      3. The process where solid change to liquid is known as _______
      4. _______ is an instrument used for measuring atmospheric pressure
      5. _______ is an apparatus used in experimnent that involves the exchange of heat between two bodies at different temperatures
      6. The root-mean square speed for average kinetic energy is given by the equation (rms) _______
      7. Thermometric liquid are _______ and _______
      8. Water expands on _______ and ice contracts on _______
      9. Thermodynamics deals with the inter-relationship between _______ and _______
      10. The three types of temperature scale are _______ and _______

    2. Question 2

      1. State two advantages of alcohol over mercury as a thermometric liquid
      2. Draw a labelled diagram of a clinical thermometer and explain how it works
      3. A constant volume gas thermometer records a pressure of 250mmHgat 0°C and 290mmHg at 100°C. Calculate the room when the gas pressure is 262mmHg.

    3. Question 3

      1. Define the following terms clearly:
        1. Specific heat
        2. Specific heat capacity
        3. Heat capacity
      2. Calculate the temperature change when 1000J of heat is suppled to 100g of water

    4. Question 4

      1. State five assumptions of the kinetic molecular theory of gas
      2. A molecule of gas has rms speed of 500m/s at 20°. What is itsrms speed at 80°C.