Which of the following statements about evaporation and boiling is FALSE?
Evaporation may take place at any temperature.
In evaporation, vapour escapes only from the surface of a liquid
The temperature remains constant as long as the liquid is boiling
The temperature at which boiling takes place can be altered by changing the external pressure
The rate of evaporation does not depend on temperature.
Correct answer is E
No explanation has been provided for this answer.
The image obtained on the screen of a pin-hole camera becomes less sharply defined when the
object is moved farther from the pin-hole
screen is moved farther from the pin-hole
object is made smaller
illumination is made more intense
pin-hole is made larger.
Correct answer is E
No explanation has been provided for this answer.
I only
II only
III only
I and III only
II and III only
Correct answer is D
No explanation has been provided for this answer.
Red and blue
Orange and green
Red and indigo
Violet and green
Yellow and red
Correct answer is C
This is called dispersion . A beam of white light passes through a prism and changes into a spectrum of colours.
The spectrum is a band of seven colours which is obtained by splitting of white light by a glass prism. The order of colours from the lower end of spectrum is violet (V), indigo (I), blue (B), green (G), yellow (Y), orange (O), and red (R).
The image is a plane mirror is
inverted, real with a magnificant of \(\frac{1}{2}\)
inverted, virtual with a magnification of 1
inverted, real with a magnification of 2
upright, virtual with a magnificent of 1
upright, real with a magnification of 2
Correct answer is D
No explanation has been provided for this answer.