71 lines
2.1 KiB
Markdown
71 lines
2.1 KiB
Markdown
# strobe light quiz answers
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Learn how to create a blinking images with a for loop. #LED #screen #plot #docs
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This is the answer key for the [strobe light quiz](/microbit/lessons/strobe-light/quiz).
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## 1. What is a for loop?
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Answers will vary. In general, for loop refers to the code that repeats for a fixed number of times. We specify the LED using x, y coordinates.
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## 2. Consider the following code
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```blocks
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for (let i = 0; i < 5; i++) {
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for (let j = 0; j < 5; j++) {
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led.plot(i, j)
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}
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}
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```
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If the rectangle below represents a board that is 5 LEDs wide and 5 LEDs tall, place an X approximately where the LED is lighted. Explain why the LED is lighted there.
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This code turns on specific LED. Plot turns on the specified LED on the LED screen. We specify the LED using x, y coordinates. The code lights on the LEDs
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``x`` - the x coordinate or horizontal position (0,1,2,3,4)
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``y`` - the y coordinate or vertical position (0,1,2,3,4)
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## 3. Consider the following code
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```blocks
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for (let i1 = 0; i1 < 3; i1++) {
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for (let j1 = 0; j1 < 3; j1++) {
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led.plot(i1, j1)
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}
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}
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```
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If the rectangle below represents a board that is 5 LEDs wide and 5 LEDs tall, place an X approximately where the LED is lighted. Explain why the LED is lighted there.
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This code turns on specific LED. Plot turns on the specified LED on the LED screen. We specify the LED using x, y coordinates.
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``x`` - the x coordinate or horizontal position (0,1,2)
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``y`` - the y coordinate or vertical position (0,1,2)
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## 4. Consider the following code
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```blocks
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for (let i2 = 0; i2 < 2; i2++) {
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for (let j2 = 0; j2 < 2; j2++) {
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led.plot(i2, j2)
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}
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}
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```
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If the rectangle below represents a board that is 5 LEDs wide and 5 LEDs tall, place an X approximately where the LED is lighted. Explain why the LED is lighted there.
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This code turns on specific LED. Plot turns on the specified LED on the LED screen. We specify the LED using x, y coordinates.
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``x`` - the x coordinate or horizontal position (0,1)
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``y`` - the y coordinate or vertical position (0,1)
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