1. 12
SchoolDD.com

www.schoolDD.com

2. www.schoolDD.com 1
12
12.1

3. - *+ ,*-

4. .-/0 *,1 -223

5. .-/0+ *-

6. 2 4516523

7. .-/0*-

8. .5
(5.23.,-6

9. 58. 455*..2 *-/ 05* -9 5239.58.,1*-

10. 29
/2)
- *,458+ * */; -5. 58
5 /..-/-50.
5-.*-

11. .458+ *-9-

12. /= *, */; 0.
5-.*-

13. 255..

14. ..6= 450.-6255..

15. .0-
/.-2?= ,0@A
1.
!
2. # !
/84

16. 2*+2-.53

17. * (B+6-
)
,1 +* -
/84

18. 2-5- (6-
) ,1 +*
6
A1
A1 N2
N2
A2
A2
N3 N3
A3
A3
s2
s1
N1
A0 N1
53

19. *596..2*+

20. 8 +*

21. /84 A
2 -.*

22. C B A
61/
A B C
5-.*-

23. 0.
@255..

24. www.schoolDD.com 2
3.
%! !
4.
'' !
12.2
(#
- .-/L.*4/51/-5,14//- .-/L5L,12.
- .-/L.*/-5

25. = 9.-6.MN2+./-5 ( T 2 v 2 λ 2
4/ f

26. )
- *20.-/L.*. ( vt )

27. .MN2+ t .S5S*
/1*84
,1 +**1.5-62 4/
0/1*TU23.,12 +**1.
1
*,1+ *1. 0*+

28. 2
253

29. *
+ AV456452 +*AV.
153

30. *53

31. .

32. ,6+M.L*..
,1-..,4*W 8

33. .6
39 +2 +*AV.
vt = 331 + 0.6t -50° C ≤ t ≤ 80° C
0.,1260A @23.2 460A ,1 +
*5.016 A.,12 +
L
.
v5L
vt

34. www.schoolDD.com 3
3

35. .,*?53

36. *20.-/L.* (v) ,*2
23

37. . v = .-/L.* (m/s)
f = 20

38. (.6/+ 3. Hz)
λ = 253

39. (m)
12.3
/0
#
53

40. * ?53

41. 2 24*-

42. .255./-5 .4 --653

43. .

44. .53

45. 255./-5,1*-

46. 2 253

47. .

48. /253

49. . 4* /84.255../+

50. -2253

51. *53

52. .

53. @
. 4* /84.255.. 23

54. .253

55. *53

56. .

57. @ 111255.
.,15

58. /25-M1

59. ?*.- 451*
v = f
/84 +2
.255
2 -/+
2 -
1,-
.-
.-
+53

60. .

61. .53

62. *
/84
255../+
255..
23

63. .53

64. *53

65. .

66. @

67. www.schoolDD.com 4
. ?A1/84 +2.255.. -61,- .2554/51
/84 *-/255

68. ./5*.- 451*,1253

69. .

70. 21,- ?;
. ?A4* 2 -.255.. -6/84/= /2453

71. .

72. .53

73. * *-//5*.- ,122 -** 451/5*,122 -/

74. 8*
*2066+ 53

75. /2.53

76. * ,53

77. /2 5 *+
- 20

78. f .*

79. +,1?20

80. --620

81. ./8+ *
1
3

82. .S;5.53

83. *20

84. *515
3

85. .T5 ,-65/-94/*53

86. ..,
-653

87. *1.5-6 2 + T5... ,, 5.53

88. ?11 8 .-/L
*9815-6 1500 m/s
2
0.MN2+..
+

89. 29, 25˚ C ? 35˚ C .-/L.*.,1?.
.-/L.*. , vt = 331 + 0.6t
23

90. . t = 25˚ C , v25 = 331 + 0.6(25) = 331 + 15 = 346 m/s
23

91. . t = 35˚ C , v35 = 331 + 0.6(35) = 331 + 21 = 352 m/s
.-/L.*.,1
+

92. 29 = 352-346 = 6 m/s Ans
.-
.- .-
+53

93. .

94. .53

95. , s = vt
= 1500 (2/2) 5

96. = 1500
s = 1500 m Ans
v = 1500
t = 2
s

97. www.schoolDD.com 5
3
*2/.- @5*2 .-*1..53

98. *20

99. * @5*2

100. /./-94/ 6.0 cm 9.6/.3

101. .8+ *

102. 220

103. 8 .-/L*
. 340 m/s
53

104. *,1+ *1.23

105. . *+

106. 3.-6253

107. --9253

108. /.-6 6.0 cm
, v = fλ
f =
=
.
= 5.67x103
Hz Ans
4
+f1@*.4 +**1. 2 -9 5-+f?5 2 451 4 + ,
111@-9*. 8 .-/L*. 340 m/s
s1 451 s2 , s = vt
s1 = vt1 = 340(2/2) = 340 m
s2 = vt2 = 340(4/2) = 680 m
111@-9*. s = s1 + s2 = 340 + 680 = 1020 m Ans
12.4 #
! %
%#
!
#
! 5 I 7 20 85-*

109. 458+ *..

110. 39

111. .53

112. 52 2? -//;/./2/ (W/m2
)
M

113. P

114. ,1 I

115. 23

116. . P = 85-* (Watt)
R = 111458+ * s
-6/84

117. ,122*
I =
s
R
t2 5-6 = 4
t1 5-6 = 2
s1 s2

118. www.schoolDD.com 6
%#
! 5 7 ?+2M

119. 6.2 -.* 2? S+65 (dB)
- *

120. 21 -622* 451*

121. 8284@A 8
#%
- .6/2*20. +*. 9-61 -622*45120

122. .*
- 5.* ( Tr ) 20 5-6,M1

123. *21 -6222

124. * ,1-

125. 5 5 60 dB
5
*,58
3

126. .* 285-* 22 -//; 4@53

127. ..?52 ,22
* 4511 -622*

128. 11 140 2/,458+
, 22* I =
=
= 10 log
23

129. . I = 22* =

130. /.-
I0 = 10-12
W/m2
22*.

131. *

132. 2;+

133. 2 +
Imax = 1 W/m2
22*2

134. *

135. 2;A
f
.6/

136. +
Tr
60 dB
0
t
s
R = 140
s P = 22

137. www.schoolDD.com 7
I = 1x10-4
W/m2
Ans
1 -622*, = 10 log
= 10 log
!
!#
= 80 dB Ans
6
6. A 451 B .,*00A ?11 50 2/ 451100 2/ /258 -6 0 A +
* 0A,*0 222 4x10-2
W/m2
B ,1 +* 222
, 22* I =
23

138. . P

139. I

140. $
%
=
%
$
IB = IA
RA
2
RB
2 = 4x10-2
502
1002
IB = 1x10-2
W/m2
Ans
7
1 -622***

141. 2;*20-6A ? 0* -

142. *

143. 2;*20A
222* 1 W/m2
1 -622*, = 10 log
= 10 log
!#
= 10 log 1012
= 10 x 12
= 120 dB Ans
*0 -
RB = 100
P
RA = 50
A
B
IA = 4x10-2
IB = ?

144. www.schoolDD.com 8
12.5
% #
%=8
?
% 9.-620

145. .* (f ) 1 -6*/

146. 8 20

147. ,1/

148. 8 253

149. 2 *,12 1 -6**
20

150. ,1* 253

151. . *,1452 20

152. .*

153. ./+ +2/-94/ 20 0 20,000
Hz *

154. 220

155. /

156. 8 20 Hz 5 53

157. /* 451*

158. 220

159. * 20,000 Hz
53

160. 3.*
#
9.-64.2
5+, .53

161. * -,124.2
5+, .53

162. **.
53

163. */2
20,000 Hz
20
53

164. /* 53

165. 3.*
20

166. +
53

167. */2
2A 3

168. .45*-M53

169. /2 ?53

170. /2
1 -6*/

171. 8 1 -6**
* -
*.

172. www.schoolDD.com 9
- *4 .* = 20 *

173. 220

174. ? 2 .20

175. .*-9= */
/- C 220

176. 256 Hz *4 . C 3. ,1220

177. 256x2 = 512 Hz ?/
=8
?
=8
? 3.*9.-653

178. * */; , .5+ 3.S. ,11.6
*

179. 220

180. f , 2f , 3f , p, nf (5r;2.+) + 9
.2- 451222*4/5120

181. 4//
- 853

182. *

183. ..24//- ,8MN
* .3

184. . /4/51+ 4//-
MN
*,?*+

185. *2041N.458+ 3.+ .3

186. . /
#
@AB
2020

187. /

188. 8* .*

189. ..,458+ * = ., r;2.+

190. 1
C
D 20 20

191. .3

192. =

193. + 9
.2-620

194. 25s 4/220

195. ?,8/L2.
20

196. 25s r;2.+

197. 2 451r;2.+

198. 3 ,1220

199. ? 2 451 3 .20

200. 25s
/258 -6 ( f , 2f , 3f , p, nf )
- 4/51/8+ ,1 f , I 451 n /-
8
*,.5 *

201. 220

202. 25s 350 Hz , r;2.+

203. 1, 2, 3 451 4 .*,
.59
r;2.+

204. 1 , f = 20

205. 25s = 350 Hz
r;2.+

206. 2 , 2f = 2(350) = 700 Hz
/; nf , In
3f , I3
2f , I2
f , I1
.5
nf , In
3f , I3
2f , I2
f , I1
S.
nf , In
3f , I3
2f , I2
f , I1
t
.5+
*.2*

207. www.schoolDD.com 10
r;2.+

208. 3 , 3f = 3(350) = 1050 Hz
r;2.+

209. 4 , = = Hz
12.6 #
@

210. %
?!
#
@

211. .-/0 2020

212. *-

213. 3.4.-/0..+*1
- 20

214. u2/+.-/0 2/-*2.
- 20

215. u2/+. */; ,1-620

216. 25s
?! ?BM;

217. 24218-/0*-

218. 3.4 20

219. .4

220. 8-/0*-

221. 3.4 -620

222. u2/+.-/0-9 23

223. .+ *-

224. . *-

225. .-/0,124.25+, .*-

226. 2

227. * 23

228. .6-6*-

229. 20

230. .3

231. =
*-

232. ..*5. S4S; + ,4*. .53

233. *,458+ 451
53

234. *

235. *1.,5*6 8+ 53

236. +

237. 255..

238. ./+ -65*6,1253

239. .

240. *
255..

241. 6+M5. ,1*-

242. 2

243. * 21,- ** , +* -

244. 5.
λ/4 λ/2

245. www.schoolDD.com 11
9
5.*-

246. ..*5. S4S; *

247. 220

248. 680 Hz 0.-/L*
.M1-9? 340 m/s ,1+ *-

249. .-9

250. 1 , 2, 451 3 23

251. . 5*6,5. ?
11
,;8 f = 680 Hz 451 v = 340 m/s
--9 λ =
/
=
0
= 0.5 m
10
,20

252. /

253. 8* .*,458+

254. 8+ *-

255. ..16.5v

256. 1.0 m 0*2.-/L 340 m/s
20

257. /

258. 8* 4* 253

259. 2

260. *
,1
= 2.
λ = 4x1 = 4 m
f , f =
=
= 85 Hz Ans
11
5. 416.5

261. v 82*9821 -6/= - 458*.2*

262. 85-*-

263. + *55.
622*.985. 4 2

264. 8+ * - +2 -942
985. 4* 10 cm -9

265. 2 2985. 4* 20 cm ,20

266. *,*.2* 0.-/L
*? 340 m/s
s1 =
=
.1
= 0.125 m Ans
s2 = ?
s1 = ?
*-

267. .-9

268. *.
*-

269. .-94
λ/4 λ/2
*-

270. .-9

271. *2
s2 =
+
=
=
2 .1
= 0.375 m Ans
λ/4

272. www.schoolDD.com 12
,
-
= 0.20
0.10 = 0.10
λ = 2x0.1 = 0.2 m
f , f =
=
.
= 1700 Hz Ans
12.7 D
6/*;.* ?BM;

273. 53

274. *,458+ *.45

275. 220

276. /-5L.2
4*. - 8 +* -451.*5-6-?,-1/-
20

277. 6/*; ,1-6 ,8-9.* - +

278. + ,
12
,20

279. 6/*;.*,458+ 2 45

280. *..2 20

281. 514 Hz 451 510
Hz
20

282. 6/*;, Δf = | f2
f1 |
= | 510
514 |
Δf = 4 Hz Ans
Δf = | f2 G f1 |
f1 = 20

283. ,458+ 1
f2 = 20

284. ,458+ 2
∆f ≤ 7 ,,1*20,84*6/*;
0.10
3λ
4
0.20
λ
4

285. www.schoolDD.com 13
12.8
I
D?
D
?BM;

286. @A (Observer) +*S

287. 220

288. 5

289. ,20

290. .458+
(Source)
1458+ 53

291. .

292. 3.@A53

293. .

294. s
1. '0J
/A!KL'=
@A ,1 +*

295. 220

296. *9 451253

297. *-95
, 4 =
/
--9 ,,1 4O =
56
/6
451 fO =
7
=
56
fs
@A 5-,1 +*

298. 220

299. /

300. 85451253

301. 9
, 4 =
/
--9 ,,1 4O =
:6
/6
451 fO =
7
=
:6
fs
458+ 53

302. .

303. @A53

304. .

305. 5-
vs t
vt
vt 23

306. . v = .-/L*.
vs = .-/L.458+
vO = .-/L.@A
fs = 20

307. *,458+
fO = 20

308. *

309. @A +
4O = 253

310. *

311. @A +

312. www.schoolDD.com 14
2. /A!KL'0J
A0
@A +458+ ,1 +*

313. 220

314. *9 4/253

315. +2
, f =
;
--9 ,,1 fO =
:7
;
451 4 =
/6
--9 fO =
:7
fs
@A +..,458+ ,1 +*

316. 220

317. /

318. 85 4/253

319. +2
, f =
;
--9 ,,1 fO =
57
;
451 4 =
/6
--9 fO =
57
fs
=A
I
D?
D
20

320. @A +,
!
MJ
A
N

321. !
1. 0458+ 53

322. .

323. @A +

324. ( vO = 0 ) ,1 fO =
6
fs
- 0@A. fO ,1
+

325. 29 --9,1 fO =
56
fs
- 0@A. 5- fO ,15 5 --9,1 fO =
:6
fs
- ,1 4O , 4O =
/7
vO vO
v
+.., s +
fO =
==
==?
fs

326. www.schoolDD.com 15
2. 0@A53

327. .

328. 458+ .+

329. ( vs = 0 ) ,1 fO =
7
@
fs
- 0@A +458+ fO ,1
+

330. 29,1 fO =
:7
@
fs
- 0@A +..,458+ fO ,15 5,1 fO =
57
@
fs
- ,1 4

331. , 4 =
/6
3. 0458+ 451@A53

332. .

333. .2-5-. 1 451 2 2-
13
0
65v S20

334. 1000 Hz 02L*.? 340 m/s .620

335. *

336. @A +23

337. .
. 0+

338. 2L 40 m/s @AS

339. .+

340. . 0+

341. 2L 40 m/s ..,@AS

342. .+

343. 5-
. @A53

344. .

345. 2L 10 m/s 0S

346. ,.

347. . @A53

348. .

349. 2L 10 m/s ..,0S

350. ,.

351. + B .
5.;
20

352. @A +, fO =
A
6
fs
. vs = 40 m/s +

353. , vO = 0
fO =
56
fs
=
5
1000 =
1000
fO = 1133 Hz Ans
. vs = 40 m/s +

354. ..,, vO = 0
fO =
:6
fs
=
:
1000 =
0
1000
fO = 895 Hz Ans
vs
vO
vO
fs = 1000
v = 340
5-

355. www.schoolDD.com 16
. vO = 10 m/s +

356. , vs = 0
fO =
:A
@
fs
=
:
1000 =
1
1000
fO = 1029 Hz Ans
. vO = 10 m/s +

357. ..,, vs = 0
fO =
5A
@
fs
=
5
1000 =
1000
fO = 970 Hz Ans
12.9
%
20 53

358. + ,.- /-.53

359. 23

360. ..-/L.458+ *.-/L.53

361. 53

362. 14?22452
S.+62 20 * -516+

363. + 93

364. .,53

365. 1453

366. .

367. @ 82 -
6+M-9 25

368. 452451 L /-.23

369. .23

370. .6+ 6+@63. 45*3

371. .6+
81,/4/
+53

372. .

373. .
458+
s
+53

374. .

375. .
53

376. 14
53

377. 14