The thermometric substance of an absolute thermometer is
alcohol
mecury
helium
platinum
Correct answer is B
Mercury is the “liquid of choice” in thermometers because mercury changes density very linearly.
8/7
4/9
9/2
4/7
Correct answer is B
A driving mirror is always a convex mirror which is always of negative focal length and always forms a virtual image
Thus if r = 1m = 100cm
f = 1/2 = -50
∴ if U = 4cm = 400cm
f = -50cm
∴1/u + 1/v = 1/f
1/400 + 1/v = -1/50
∴ -1/v = 1/400 + 1/50
-1/v = (1 + 8)/400 = 9/400
∴ v = -400/9
v = 4/9
improving the sharpness
creating an inverted image
magnification of the image
erection of the image
Correct answer is D
The extra lens in the terrestrial telescope mounted at the middle between the objective lens and the eye piece is to re-invert the image so that it is upright.
70°
45°
25°
20°
Correct answer is D
When ever a ray of light is incident on a plane mirror at an angle of incidence l, if the mirror is then rotated through an angle θ, then the reflected ray is rotated through an angle twice θ
So if θ = 35°, then the reflected ray is rotated through 2 x 10o = 20°
Ice cubes are added to a glass of warm water. The glass and water are cooled by
conduction only
convection only
conduction and convection
convection and radiation
Correct answer is C
No explanation has been provided for this answer.