Examsnet
Unconfined exams practice
Home
Exams
Banking Entrance Exams
CUET Exam Papers
Defence Exams
Engineering Exams
Finance Entrance Exams
GATE Exam Practice
Insurance Exams
International Exams
JEE Exams
LAW Entrance Exams
MBA Entrance Exams
MCA Entrance Exams
Medical Entrance Exams
Other Entrance Exams
Police Exams
Public Service Commission (PSC)
RRB Entrance Exams
SSC Exams
State Govt Exams
Subjectwise Practice
Teacher Exams
SET Exams(State Eligibility Test)
UPSC Entrance Exams
Aptitude
Algebra and Higher Mathematics
Arithmetic
Commercial Mathematics
Data Based Mathematics
Geometry and Mensuration
Number System and Numeracy
Problem Solving
Board Exams
Andhra
Bihar
CBSE
Gujarat
Haryana
ICSE
Jammu and Kashmir
Karnataka
Kerala
Madhya Pradesh
Maharashtra
Odisha
Tamil Nadu
Telangana
Uttar Pradesh
English
Competitive English
Certifications
Technical
Cloud Tech Certifications
Security Tech Certifications
Management
IT Infrastructure
More
About
Careers
Contact Us
Our Apps
Privacy
Test Index
BITSAT 2018 Slot 2 Solved Paper
Show Para
Hide Para
Share question:
© examsnet.com
Question : 6
Total: 150
A train moves towards stationary observer with speed
34
m
∕
s
. The train blows whistle and its frequency is registered by the observer as
f
1
. If the train's speed is reduced to
17
m
∕
s
, the frequency registered is
f
2
. If the speed of sound is
340
m
∕
s
, then the ratio
t
1
f
2
is
19
18
18
19
2
1
∕
2
Validate
Solution:
According to Doppler’s effect, the approximate frequency heard by the stationary observer,
v
=
v
v
−
v
s
v
0
Case (i)
v
s
=
34
m
∕
s
where,
v
=
speed of sound in air,
u
s
=
speed of source
and
v
0
=
frequency of the source.
∴
v
1
=
340
340
−
34
v
0
=
340
306
v
0
.........(i)
Case (ii)
v
s
=
17
m
∕
s
∴
v
2
=
340
340
−
17
v
0
=
340
323
v
0
........(ii)
From Eqs. (i) and (ii), we get
∴
v
1
v
2
=
340
∕
306
340
∕
323
⇒
323
306
≈
19
18
© examsnet.com
Go to Question:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
Prev Question
Next Question
Examsnet