Question

Somu wents to watch movie with his parents. In the dark, he found a small

beam of light within which millions of tiny particles were dancing. He
thought, when there was light, no such beam appears. He was surprised.


Answer the following questions based on above information.

(i) What were the tiny partiles?

(ii) What a single term can be used for this phenomena?

a) reflection b) refraction

c) dispersion d) scattering

(iii)Define the above term. 18 (iv) Select the solution that shows the above phenomena

a) soap solution b) salt solution

c) sugar solution d) muddy water

(v)Give one example of this effect observed in your surroundings.​

Answer 1

Explanation:

1) However, on the following page, the term “particles” is used to refer to atoms: “All matter is composed of tiny, indivisible particles called atoms” (p. 158s).

2)The law of reflection states that the angle of reflection equals the angle of incidence.

3)The phenomenon that is depicted here is the reflex action which is an involuntary and instant movement in response to stimuli.

(ii) The term for the point of contact between the two nerve cells is called the synapse.

(iii) (1). Sensory (Afferent neuron) (2). Dorsal ganglion

(3). White matter (4). Grey matter

(iv) The function of 5 (Synapse): It transmits the sensory impulse from sensory neurons to the motor neurons.

The function of 6 (Motor neuron/Efferent neuron): It transmits the command to the effectors part (e.g. muscles).

v) The arrangement of neurons in the spinal cord differs from that of the brain. In the brain, Gray matter is present on the outside and white matter on the inner side. In Spinal cord, white matter is present on the outside and Gray matter on the inner side.

4)Give some examples of Tyndall effect observed in your surroundings? Answer: Examples of Tyndall effect (i) When sunlight passes through the canopy of a dense forest. (ii) When a fine beam of light enters a dark room through a small hole.