The percentage of solar radiation absorbed by all the green plants for the process of photosynthesis is about
Which group of organisms are not constituents of a food chain?
Select the correct option:
In the given food chain, suppose the amount of energy at fourth trophic level is 5 kJ, what will be the energy available at the producer level?
Grass → Grasshopper → Frog → Snake → Hawk
In a food chain, the third trophic level is always occupied by
The strength of magnetic field inside a long current carrying straight solenoid is
A constant current flows in a horizontal wire in the plane of the paper from east to west as shown in Figure. The direction of magnetic field at a point will be North to South
In the arrangement shown in Figure there are two coils wound on a non-conducting cylindrical rod. Initially the key is not inserted. Then the key is inserted and later removed. Then
Commercial electric motors do not use
A uniform magnetic field exists in the plane of paper pointing from left to right as shown in Figure. In the field an electron and a proton move as shown. The electron and the proton experience
For a current in a long straight solenoid N- and S-poles are created at the two ends. Among the following statements, the incorrect statement is
A circular loop placed in a plane perpendicular to the plane of paper carries a current when the key is ON. The current as seen from points A and B (in the plane of paper and on the axis of the coil) is anti clockwise and clockwise respectively. The magnetic field lines point from B to A. The N-pole of the resultant magnet is on the face close to
If the key in the arrangement is taken out (the circuit is made open) and magnetic field lines are drawn over the horizontal plane ABCD, the lines are
Two resistors of resistance 2 Ω and 4 Ω when connected to a battery will have
An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?
In an electrical circuit two resistors of 2 Ω and 4 Ω respectively are connected in series to a 6 V battery. The heat dissipated by the 4 Ω resistor in 5 s will be
In an electrical circuit three incandescent bulbs A, B and C of rating 40 W, 60 W and 100 W respectively are connected in parallel to an electric source. Which of the following is likely to happen regarding their brightness?
If the current I through a resistor is increased by 100% (assume that temperature remains unchanged), the increase in power dissipated will be
A cylindrical conductor of length l and uniform area of cross-section A has resistance R. Another conductor of length 2l and resistance R of the same material has area of cross section
What is the maximum resistance which can be made using five resistors each of 1/5 Ω?
A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross section of the filament in 16 seconds would be roughly
Electrical resistivity of a given metallic wire depends upon
In the following circuits, heat produced in the resistor or combination of resistors connected to a 12 V battery will be
The focal length of the eye lens increases when eye muscles
When light rays enter the eye, most of the refraction occurs at the
Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?
The clear sky appears blue because
Which of the following phenomena of light are involved in the formation of a rainbow?
A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power
Rays from Sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of its image is equal to the size of the object?
Magnification produced by a rear view mirror fitted in vehicles
A 10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror. The focal length of this mirror is
Which of the following can make a parallel beam of light when light from a point source is incident on it?
The theory of evolution of species by natural selection was given by
In peas, a pure tall plant (TT) is crossed with a short plant (tt). The ratio of pure tall plants to short plants in F2 is
A zygote which has an X-chromosome inherited from the father will develop into a
If a round, green seeded pea plant (RR yy) is crossed with wrinkled, yellow seeded pea plant, (rr YY) the seeds produced in F1 generation are
A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because
Two pink coloured flowers on crossing resulted in 1 red, 2 pink and 1 white flower progeny. The nature of the cross will be
Which among the following diseases is not sexually transmitted?
The correct sequence of organs in the male reproductive system for transport of sperms is
Length of pollen tube depends on the distance between
Vegetative propagation refers to formation of new plants from