Science Class 7th
321. The angle of incidence for which the corresponding angle of refraction is 90o is called?
A) Angle
B) Critical angle
C) Refraction
D) None
322. Maximum refraction occurs at ______ angle.
A) Right
B) Critical
C) None
323. Critical angle for water is?
A) 49o.
B) 50o
C) 45o
D) None
324. Critical angle of glass is?
A) 90
B) 56
C) 42o
D) 60
325. When the angle of incidence becomes becomes greater than the critical angle, then no refraction occurs and light reflects back, the phenomenon is called?
A) External reflection
B) Total internal reflection
C) Critical reflection
326. The conditions for Total internal reflection are:
A) Light must enter from a denser medium to rare medium
B) Angle of incidence must be greater than critical angle
C) Both ‘a’ and ‘b’
327. A reflecting prism is made of transparent glass which has _____ surfaces.
A) 3 rectangular surfaces
B) 2 triangular surfaces
C) Both ‘a’ and ‘b’
D) None of these
328. Each triangular surface has one angle of ______ and other two angles of 45o?
A) 90o
B) 45
C) 60
D) 180
329. Total internal reflection occurs in?
A) Reflecting prism
B) Periscope
C) Mirage
D) All of these
330. Which of the following is natural optical phenomenon?
A) Mirage
B) Prism
C) Periscope
D) None
331. In hot days, we see inverted images of distant objects on roads because of total internal reflection, the phenomenon is called?
A) Mirage
B) Reflection
C) Refraction
D) None
332. Mirage is optical_____.
A) Reality
B) Virtuality
C) Illusion
D) None
333. A fish and diver is able to see objects in the side and bottom of pond due to?
A) Refraction
B) Reflection
C) Total internal reflection
D) None
334. The fish or diver is able to see objects outside pond due to?
A) Total internal reflection
B) Refraction
C) Reflection
D) None of these
335. When beam of sun light is passed through prism, it splits up in _____ colors.
A) 8
B) 6
C) 7
D) 10
336. The phenomena of splitting light into its component colors is called______ of light.
A) Dispersion
B) Convergence
C) Inversion
D) None
337. The band of seven colors obtained is called?
A) Spectrum of light
B) Group of light
C) Band of light
D) None of these
338. Seven colors of spectrum can be denoted by?
A) VIBGYOR
B) VEBYOR
C) YORBOG
D) None
339. Rainbow is an example of?
A) Reflection of light
B) Total internal reflection
C) Dispersion of light
340. Red color appears on the _______ side of rainbow.
A) Middle
B) Upper
C) Bottom
D) Not at all
341. Violet color appears on the _________ side of rainbow
A) Upper
B) Middle
C) Bottom
D) Lower side
342. Colors that can be used to make any other color is called ______ color.
A) White
B) Primary
C) Secondary
D) None
343. The Primary colors are?
A) Red
B) Blue
C) Green
D) All of the above
344. Colors produced by mixing any two primary colors are called ______ colors.
A) Secondary
B) Primary
C) Tertiary
D) None
345. Peacock blue is ______ color.
A) Primary
B) Secondary
346. Peacock blue is which color?
A) Sky blue
B) Blue
C) Peacock color
D) Cyan
347. Which of the following are secondary colors?
A) Magenta
B) Yellow
C) Both ‘a’ and ‘b’
D) None
348. With the help of ______ Newton demonstrated that white light is combination of 7 different colors.
A) Prism
B) Newton color disc
C) Periscope
D) None
349. The color of an object is the color which it?
A) Reflects
B) Absorb
C) Refract
D) None
350. Peacock blue is which color?
A) Sky blue
B) Blue
C) Peacock color
D) Cyan