Light Practice Questions
SPM (Malaysia) · SPM Physics · 132 free MCQs with instant results and detailed explanations.
132
Total
43
Easy
69
Medium
20
Hard
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Sample Questions from Light
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
Which phenomenon explains why a straw looks bent when placed in a glass of water?
A.
Reflection
B.
Refraction
C.
Diffraction
D.
Absorption
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Correct Answer: B
Refraction occurs when light passes from air into water and changes speed, causing the light rays to bend, making the straw appear bent.
Q2
Easy
If a ray of light strikes a plane mirror at an angle of 30 degrees, what will be the angle of reflection?
A.
30 degrees
B.
60 degrees
C.
90 degrees
D.
15 degrees
Show Answer & Explanation
Correct Answer: A
According to the law of reflection, the angle of incidence is equal to the angle of reflection. Therefore, if the angle of incidence is 30 degrees, the angle of reflection is also 30 degrees.
Q3
Easy
What is the primary reason for the dispersion of light in a prism?
A.
Different colors have different speeds in glass.
B.
Light bends due to diffraction.
C.
Colors absorb heat differently.
D.
All colors reflect equally.
Show Answer & Explanation
Correct Answer: A
Different colors of light have different wavelengths, which causes them to travel at varying speeds when passing through a medium like glass. This speed difference leads to bending at different angles, resulting in dispersion.
Q4
Medium
What is the critical angle for total internal reflection when light travels from glass (n = 1.5) to air (n = 1.0)?
A.
42 degrees
B.
30 degrees
C.
48 degrees
D.
60 degrees
Show Answer & Explanation
Correct Answer: A
The critical angle can be calculated using Snell's law: sin(ฮธc) = n2/n1. Here, ฮธc = sin^(-1)(1.0/1.5) which gives approximately 42 degrees.
Q5
Medium
When white light passes through a prism, which color is refracted the least?
A.
Red
B.
Blue
C.
Green
D.
Violet
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Correct Answer: A
In a prism, red light is refracted the least because it has the longest wavelength while violet light is refracted the most due to its shorter wavelength.
Q6
Medium
What phenomenon explains why a straw appears bent when placed in a glass of water?
A.
Reflection
B.
Refraction
C.
Diffraction
D.
Dispersion
Show Answer & Explanation
Correct Answer: B
Refraction is the bending of light as it passes from one medium to another; in this case, from air to water, causing the straw to appear bent.
Q7
Medium
Which of the following statements about concave mirrors is NOT true?
A.
They can form virtual images.
B.
They always produce real images.
C.
The focal point is located in front of the mirror.
D.
They can produce inverted images.
Show Answer & Explanation
Correct Answer: B
Concave mirrors can produce both real and virtual images depending on the object's position relative to the focal point; they do not always produce real images.
Q8
Hard
A converging lens has a focal length of 20 cm. An object is placed 60 cm away from the lens. What is the distance of the image from the lens?
A.
15 cm
B.
30 cm
C.
40 cm
D.
45 cm
Show Answer & Explanation
Correct Answer: C
Using the lens formula 1/f = 1/v - 1/u, where f is the focal length (20 cm), u is the object distance (-60 cm), we find v (image distance). The calculation yields v = 40 cm, indicating the image is located 40 cm from the lens.
Q9
Hard
A lens has a focal length of 20 cm. An object is placed 50 cm from the lens. What is the image distance from the lens?
A.
15 cm
B.
33.3 cm
C.
40 cm
D.
25 cm
Show Answer & Explanation
Correct Answer: B
Using the lens formula 1/f = 1/v - 1/u, where f is the focal length (20 cm), u is the object distance (-50 cm), we can find v (image distance). Rearranging gives v = 1/(1/f + 1/u) = 1/(1/20 - 1/50) = 33.3 cm.
Q10
Hard
If light travels from a medium with a refractive index of 1.5 to air (refractive index = 1), what is the critical angle for total internal reflection?
A.
41.8 degrees
B.
48.6 degrees
C.
53.1 degrees
D.
60.0 degrees
Show Answer & Explanation
Correct Answer: A
Using the formula for critical angle ฮธc = sin^(-1)(n2/n1), where n1 = 1.5 (medium) and n2 = 1 (air), we find ฮธc = sin^(-1)(1/1.5) = 41.8 degrees. This angle is where total internal reflection occurs.
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Light โ SPM (Malaysia) SPM Physics Practice Questions Online
This page contains 132 practice MCQs for the chapter Light in SPM (Malaysia) SPM Physics. The questions are organized by difficulty โ 43 easy, 69 medium, 20 hard โ so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.