Q. Four students observed the specimens of two plants and sketched them as shown below. They noted in their notebook the identification and the names of the group to which these plants belong (a) A – moss ; Bryophyta B – fern ; Pteridophyta (b) A – pine ; Gymnosperm B – leafy plant ; Angiosperm (c) Both A and B are moss and belong to Bryophyta (d) Both A and B are ferns and belong to Pteridophyta. Ans: (a) A – moss ; Bryophyta B – fern ; Pteridophyta Q. A strong transverse horizontal pulse, created at one end of a string, is observed to complete 5 journeys along its length, before fading out. The initial reading of the stop clock used in the experiment was 5 s and the final reading was 55 s. If the length of the string for one journey is L metre, the speed of the pulse, through the string is : (a) (L/55) ms21 (b) (L/50) ms21 (c) (L/11) ms21 (d) (L/10) ms21 Ans: (d) (L/10) ms21 Q. To determine the speed of a pulse through a stretched string a student can ...