CBSE - X
Question 1
To a bird in air, a fish in water appears to be at 30 cm from the surface. The refractive index of water with respect to air is 
. The real depth of the fish is ____ cm.
A) 20
B) 30
C) 40
D) 35
Question 2
If two identical prisms are placed parallel to each other in upside down position with each other, then the light dispersed by prism ABC is recombined by prism A'B'C'. The light coming out of the prism A'B'C' is of ____ colour.
A) red
B) white
C) blue
D) green
Question 3
When a potential difference of 250 V is applied across a resistor, 0.5 A current flows in it. Then the rate at which heat is produced by the resistor is ____ J/s.
A) 500
B) 62.5
C) 1520
D) 125
Question 4
By changing the polarity of the electricity (i.e., changing the direction in which it flows) we change the polarities of the electromagnet.
A) True
B) False
Question 5
In the given reaction 
the substance oxidised is ____.
A) 
B) 
C) 
D) S
Question 6
reacts with dilute
to form ____ gas.
A) 
B) 
C) CO
D) 
Question 7
The minerals from which metals are extracted profitably are called ____.
A) alloys
B) mixtures
C) ores
D) compounds
Question 8
Percentage of oxygen and carbon dioxide in the atmosphere are balanced by ____.
A) photosynthesis
B) respiration
C) combustion
D) photosynthesis and respiration
Question 9
When a person is in coma stage, the system other than nervous system that helps in carrying impulses is ____.
A) digestive system
B) endocrine system
C) skeletal system
D) muscular system
Question 10
Ratio 9:3:3:1 refers to ____.
A) Dihybrid cross
B) Monohybrid cross
C) Trihybrid cross
D) Polyhybrid cross