Write laws of refraction. Explain the same with the help of ray diagram, when a ray of light passes through a rectangular glass slab.
Laws of refraction:
or
= refractive index of the second medium with respect to the first medium.
For a glass slab as shown in figure
i = angle of incidence
r1 = angle of reflection
Two stones are thrown vertically upwards simultaneously with their initial velocities u1and u2 respectively. Prove that the heights reached by them would be in the ratio of u12 : u22
(Assume upward acceleration is –g and downward acceleration to be +g ).
The height reached by any stone can be calculated by using the third equation of motion.
We can use the fact, that at the highest point the velocity will be zero. The acceleration due to gravity will retard the particles.
Therefore, the height raised for any particle will be given as:
Therefore
Obtain a relation for the distance travelled by an object moving with uniform acceleration in the interval between 4th and 5th seconds.
Distance travelled in nth second by any particle is equal to the difference of distances travelled in n seconds and n -1 seconds.
For example. distance travelled in the fourth second is the difference of distance travel in four seconds and three seconds.
Hence, by using the second equation of motion we can find out the distance travelled in nth second.
If the initial velocity is zero,
In that case, the distance travelled in the fourth second and fifth second will be in the ratio of 7:9.
View Full Answer(1)The barrel of a fountain pen, cylindrical in shape, is 7 cm long and 5 mm in diameter. A full barrel of ink in the pen is used upon writing 3300 words on average. How many words can be written in a bottle of ink containing one-fifth of a litre?
3300 words can be written with 0.001375 L of ink
So with 1L of ink 3300/0.001375 words can be written=2400000
So with 1/5th of a litter 2400000/5 words can be written=48000
View Full Answer(2)How are the activities of gastro-intestinal tract regulated?
Activities of digestive system regulate both Harmon and neural reflexes
View Full Answer(2)In which plant will you look for mycorrhiza and coralloid roots? Also, explain what these terms mean.
Mycorrhiza, which is also known as ‘fungus-root’, is basically a mutually beneficial relationship between that of plant root and a fungus. In most cases, the fungus grows within the roots of the plants and helps the plant to absorb water and nutrients, and in return, the plant provides the fungus with food. E.g., Pinus. In some cases, the fungus could be harmful to the plants.
Coralloid Roots: These roots are associated with nitrogen-fixing cyanobacteria. In coralloid roots, the nodules are formed in large numbers, in the roots giving them coralloid appearance. E.g. Cycas and plants of Leguminosae.
View Full Answer(1)How are the male and female gametophytes of pteridophytes and gymnosperms different from each other
The size of gametophyte of of pteridophytes quite large compare to gymnosperm's gametophytes. Gametophyte of pteridophytes are photosynthetic in nature while gametophyte of gymnosperms are are not photosynthetic in nature
View Full Answer(2)Comment on the lifecycle and nature of a fern prothallus
Fern, which is a type of pteridophytes; reveals a haplo-diplontic state. In this situation, both the stages of gametophytic and sporophytic are multicellular. The diploid sporophyte is represented by a prepotent and independent, photosynthetic, vascular plant body. The haploid gametophyte, which is also independent in nature, but the duration of its life is shorter than that of the sporophytes.
Differentiate between
a. Bract and Bracteole
b. Pulvinus and petiole
c. Pedicel and peduncle
d. Spike and spadix
e. Stamen and staminoid
f. Pollen and pollenium
Ans:
a. The bracteolate is found between the bract and flower while a bract is found towards the base of the pedicle.
b. Petiole is a subcylindrical stalk that connects the lamina with the leaf base while Pulvinus is a swollen leaf base which is found in leguminous plants.
c. The Peduncle is a stalk of the whole inflorescence while a pedicle is the stalk of a flower.
d. Spadix is covered by several large bracts known as spates while in spike sessile flowers are attached on an elongated peduncle.
e. Every stamen represents a male reproductive organ and androecium is composed of stamens. Staminode is a sterile stamen.
f. Polonium is defined as the group of pollen grains while a pollen is a male gametophyte of angiosperms.
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