- 31. You are putting up your Christmas tree and decide to begin untangling the lights sc wrap them around your tree. Once you untangle them, you plug them in to make st working. Unfortunately,none of the lights seem to light up! You look carefully at th lights and realize that one light bulb seems to be loose. You screw the light bulb ba suddenly the whole strand lights up. How are your Christmas lights connected? Bri why they were not lit up when the bulb was loose. (/2T) __
- Other forms of energy : __ (eg, battery) __ (eg, in a star) __ (eg, from a bulb or the sun) __ , or heat (eg, your oven/stove) __ __ (eg, a moving car)
- Thue/False (12 marks) __ 1. The universal wave equation can be used to calculate the amplitude of a wave. __ 2. When a student sends a positive pulse towards the free-end of a spring, the reflected pulse returns as a negative pulse. __ 3. The scientific musical scale is based on a frequency of 200 Hz , and each octave is twice the frequency of the octave before it. __ 4. The principle of superposition relates the three wave quantities of speed wavelength, and frequency. __ 5. The nodal point of a standing wave forms due to the continuous destructive interference of two waves at that point __ 6. The intensity of sound is could be measured in kilowatts per cubic centimetre __ 7. As the air temperature decreases, the speed of sound also decreases. __ 8. An object which completes 100 vibrations in 2.5 s produces sound audible to most humans. __ 9. In humans with healthy hearing, the audible frequencies range from 20 Hz to 20000kHz. __ 10. In general, sound travels most quickly in solids and most slowly in gases. __ 11. If tuning forks with frequencies of 512 Hz and 514 Hz are sounded at the same time, 10 beats will be heard in 5.0 s. __ 12. Decreasing the density of a vibrating string will increase its frequency.
- Question 19 (Mandatory) (1 point) A radioactive sample with an initial mass of 35 mg has a half-life of 3 days. Which of the following equations models the exponential decay for time, t, in days? a) A=35(2)^(1)/(3) b) A=35((1)/(2))^(1)/(3) c) A=35(2)^(3)/(2) d) A=35((1)/(2))^(3)/(2)
- One milliampere (mA) equals __ amperes. (Objective 1-1 square
