World time physics

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1. Smallest unit of measurement by;
Measurement tape → 1 cm or 1mm
Meter rule or half meter rule → 0.1 cm or 1 mm
Vernier caliper → 0.01 cm or 0.1 mm
Screw gauge → 0.001 cm or 0.01 mm
2. θ = s/r
3. 2π rad = 3600
4. 3600 = 1 revolution
5. 1 radian = 57.30
6. 1 degree = 60 minute
7. 1 minute = 60 seconds
8. Angle at circle is 2π radian.
9. Angle at sphere is 4π steradian.
10. Volume of slid cylinder = πr2l
11. Area of sphere = 4πr2
12. Volume of sphere = 4/3 πr3
13. Dimension of velocity = [LT-1]
14. Dimension of acceleration= [LT-2]
15. Energy of photon; E = hf
16. Time period of pendulum; T = 2π


17. Commutative property of vector= A+B = B+A
18. Fx =F cosθ
19. Fy = Fsinθ
20. F =
21. A.B = AB cos θ
22. A x B = AB sin θ
23. Scalar product; work and power
24. Vector product; torque
25. τ = r x F
26. First condition of equilibrium; ∑F = 0
27. Second condition of equilibrium; ∑τ = 0


28. v = s/t
29. a = v/t
30. vf = vi +at
31. s = vit + ½ at2
32. 2as = vf2 – vi2
33. S = vave x t
34. Vave =( vi + vf )/2
35. g = 9.8 ms-2 = 32 ft-2
36. F = ma
37. a = v/t
38. P = mv
39. P = F t
40. Impulse; J = F x t = ∆P
41. J = ∆P
42. Law of conservation of momentum; ∆p = 0
43. Elastic collision in one dimension; [v1 + v2] = [v1’+ v2’]
44. Magnitude of projectile velocity; Vf =
45. Height of projectile; H = vi2sin2θ/2g
46. Time of flight; T = 2 vi sinθ/g
47. Time of summit or time to reach to highest point; T = vi sinθ/g
48. Range; R = vi2 sin 2θ/g
49. Rmax = vi2/g
50. R = Rmax at 450
Work and Energy
51. W = Fd cosθ
52. Power; p=W/t or p =Fv
53. 1 watt = Js-1
54. 1 hp = 746 watts
55. K.E = ½ mv2
56. P.E = mgh
57. Efficiency = output/input = W x D/P x d
58. Absolute potential energy =Fr = - GmMe/Re (- because work is done against gravity)
59. Gravitational potential = E/m = GMe/Re
60. For escape velocity compare K.E with Absolute potential energy; vesc = → vesc =
61. G = 6.67 x 10-11 Nm2kg-2
62. Re = 6.4 x 106 m
63. Me = 6 x 1024 kg
64. Vesc = 11.2 x 103 ms-1
65. Wh = K.E + fh → (Wh = loss in potential energy)
66. Loss in P.E = Gain inn K.E + work done against friction
67. E = mc2 →(c= 3 x 108 ms-1)
Rotational and circular motion
68. Angular velocity; ω = ∆θ/∆t
69. Angular acceleration; α = ∆ω/∆t → a = α x r
70. v = r ω
71. Fc = mv2/r
72. ac = -(v2/r)
73. Centrifugal force= mv2/r
74. F sin θ = mv2/r
75. F cos θ = mg
76. Tan θ = v2/gr
77. Τorque = r F = rma = rm (rα) =( r2m)α = I α
78. Moment of inertia; I = mr2
79. Ring or thin walled cylinder inertia(I) = MR2
80. Disc or solid cylinder inertia = ½ MR2
81. Disc inertia = ½ M (R22 + R12 )
82. Solid sphere inertia = 2/5 MR2
83. Solid rod or meter stick inertia = 1/12 Ml2
84. Rectangular plate inertia = 1/12 M (a2+b2)
85. Angular momentum = L = r x p = r mv = rmrω =r2mω = Iω
86. L = rmv → L/t = rmv/t = rma = rF = τ
87. L/t = τ
88. Linear kinetic energy = ½ mv2
89. Rotational kinetic energy = ½ Iω2
90. Velocity of hoop = v =
91. Velocity of disc = v =
92. Critical velocity = v = 7.9 km2
93. The orbital velocity = v =
94. Lift at rest → T =w
95. Lift moving downward → T = w – ma
96. Lift moving upward → T = w + ma
97. Lift falling freely = T mg-ma = 0
98. Frequency for artificial satellite → f =
Fluid dynamics
99. Drag force → Fd = 6 πη r v
100. Terminal velocity → vt =
101. Continuity equation → A1 v1 = A2 v2
102. Av=∆V/∆t = constant
103. ∆m/∆t = ρ ∆V/∆t
104. Bernoulli’s Equation = P + ½ ρv2 + ρgh = constant
105. Torricelli’s Theorem → v =
106. Flow meter or the venture meter → v1 =
Oscillation
107. Frequency → f=1/T
108. Angular frequency → ω = 2πf
109. Time period → T = 2π/ω
110. Velocity of projection → vy = ω
111. Simple pendulum time period → T = 2π
112. Simple pendulum potential energy = ½ kx2
113. Simple pendulum kinetic energy = ½ kx02 -½ kx2
114. Total energy of simple pendulum = ½ kx02
115. Resonance frequency = Fn = nf1
116. Phase → θ =ω t
Waves
117. Transverse wave speed →
118. Longitudinal waves speed →
119. Phase change→ 2π = λ
120. Phase difference → δ = 2π/λ
121. Speed of sound by newton → v = = 281 ms-1
122. Laplace correction → v = = 332 ms-1
Chap No.11 ELECTROSTATICS
123. 1 e = 1.602 x 10-19 C
124. Q = ne
125. Coulomb’s Law; F = k
126. K =
127. K = 9.0 x 109 N m2 C-2
128. εo = 8.85 x 10 -12 C2 N-1 m-2
129. εr =
130. Fmed =
131. E = = = K
132. Ф = E A cos θ = N m2 C-1
133. Ф =
134. E due to sheet of charge; E =
135. E due to charge palates; E =
136. V = = Volt = Joule / Coulomb
137. Electric potential energy; U =
138. Electric potential; V = = =
139. Potential Gradient = E = -
140. 1 eV =1.602 x 10-19 C x 1V → (1 eV = 1.602 x 10-19 J)
141. C = = C V-1 = farad
142. Charge density; σ =
143. Cvac = = =
144. εr = Cmed / Vvac
146. Capacitors In Series;
147. Q = Q1 = Q2 =Q3
148. V =V1 + V2 + V3
149. 1/Ce = 1/C1 + 1/C2 + 1/C3
150. Capacitors In Parallel;
151. Q = Q1 = Q2 = Q3
152. V = V1 + V2 +V3,
153. Ce = C1 + C2 + C3
154. Electric dipole; P = q d
155. Energy = U = = (Ed)2
156. Energy density; E2
157. Maximum charge on capacitor = C x e.m.f
158. q/q0 = 63.2 % →for charging
159. q/q0 = 36.7 % →for discharging
160. q = q0 (1-e-t/RC ) →for charging
161. q = q0 e-t/RC →for discharging

Chap No. 12 CURRENT ELECTRICITY
162. Current, I = Q/t → C s-1 = A
163. Drift velocity order = 10-5 m/s.
164. V = IR
165. Tan θ = I/V = 1/R
166. Resistance, R = V/I → 1Ω = 1V/1A
167. R = ρ L/A → Ω.m
168. Conductance, G = 1/R → Siemen(S) or mho
169. Conductivity, σ = 1/ρ =L/RA →mho/m or S/m
170. Pure metals R inc with T inc.
171. Electrolytes and insulators, R dec with T inc.
172. ΔR = αR0 T → RT = R0 (1+αT)
173. Temperature co-efficient of Resistance, α = RT – R0/R0T → K-1
174. Resistivity, ρ T = ρ 0 (1+αT) OR α = ρ T – ρ 0/ ρ 0T → K-1
175. Electromotive Force, ε = W/q → 1 volt = 1 joule/coulomb
176. Open circuit, I = 0 so V= ε
177. Terminal Voltage, Vt = ε - Ir
178. Power, P = W/t = VI → 1 Watt = 1V x 1A
179. 1 kWh = 1 unit of electrical energy
180. 1 J = 1W x 1s
181. Maximum output power, (Pout)max = ε2 /4r = ε2 /4R
182. Thermo emf, ε = αT + ½ βT2
183. KCL, ƩI = 0
184. KVL, Ʃε = ƩV = ƩIR
185. KCL based on L.O.C.O.CHARGE
186. KVL based on L.O.C.O.ENERGY
187. Wheatstone Bridge, X = PQ/R
188. Potentiometer, ε2 /ε1 = I2 /I1
189. Tan θ = I/V = 1/R

Chap No. 13 ELECTROMAGNETISM
190. Force on current carrying wire, F=BIL sin θ.
191. Magnetic field or magnetic induction, B = F/IL →1 tesla =1 NA-1 m-1 = 1 Wb m-2
192. 1 T = 104 G
193. Magnetic Flux, Ф = B A cos θ → 1 Wb = 1 N m A-1.
194. Ampere’s Law, B I/r = μ0 (I/2πr) OR ƩB.ΔL = μ0 I
195. Bnet = B1 + B2
196. Magnetic field due to current carrying solenoid, B = μ0 n I → n=N/L
197. Motion of charge particle in uniform magnetic field, F=q v B sin θ
198. Centripetal Force = Magnetic force → mv2/r = qvB
199. Time period of charge particle in B, T = 2πm/qB
200. Frequency of charge particle in B, f = qB/2πm
201. Velocity selector, FE = FM → qE = qvB → v = E/B
202. Torque on current carrying coil, τ = NBIA cos θ
203. Ρestoring torque, τ = C θ
204. Galvanometer, NBIA cos θ = C θ → I = Cθ/NAB → I θ
205. Conversion of galvanometer into ammeter, small R connected in parallel
206. Conversion of galvanometer into voltmeter, large R in series are connected
207. Ammeter, Rs = Rg Ig / (I – Ig) → Ideal ammeter → 0 R
208. Voltmeter, Rh = (V/Ig) – Rg → Ideal voltmeter → infinite R

Chap No. 14 ELECTROMAGNETIC INDUCTION
209. Faraday’s Law, ε N (ΔФ/Δt) → ε = N (ΔФ/Δt )
210. Lenz Law, ε = –N (ΔФ/Δt )
211. Flux motional emf, ε = Blv sin θ
212. Rate of work done, W= Bilv
213. Rate of production of electrical energy, energy =ε I
214. W = energy → Bilv = εI → ε = Blv
215. Power, P = F v
216. ε = L ΔI/Δt or ε = N ΔФ/Δt → LI = NФ
217. Self-Inductance, L = NФ /I
218. ε = M ΔI/Δt or ε = N ΔФ/Δt → MI = NФ
219. Mutually inductance, M = NФ /I
220. F = 1/T
221. Induced emf, ε = NAB cosωt or NAB ω sinωt
222. ε = εmax sin ωt
223. Back emf, V = ε + IR
224. Ns / Np = Vs / Vp = Ip /Is

Chap 16 PHYSICS OF SOLIDS
225. Elastic modulus =
226. Tensile stress =
227. Tensile strain =
228. Young modulus = = Nm-2
229. Shear stress =
230. Shear strain = = tan θ
231. Shear modulus = rigidity modulus = =
232. Bulk or volume stress =
233. Bulk modulus (in fluids) = Δp =
234. Volume strain =-
235. Bulk modulus = =
236. Stress strain (Hook’s law)
237. A = r2
238. W = ½Fe (work done on stretching wire).
239. Strain energy = ½ F e
240. Strain energy per unit volume = = ½ (stress) (strain )

Chap 18 DAWN OF MODERN PHYSICS
241. E = m0 c2
242. L= L0
243. T = t0
244. M = m0
245. λmax T = 0.2898 x 10-2 m k (Wein’s displacement law)
246. E = σ T4 (Steffan-Bolts Law)
247. σ = 5.67 x 10-8 Wm-1 K-4
248. E = n h f
249. K.Emax = e V0
250. K.Emax = h f – Ф
251. H f0 = Ф =
252. K.Emax = hf - Hf0
253. Hf = K.E +hf’
254. P=
255. Δλ = 1-
256. = + 1-
257. Ephoton = Eelectron + Epositron
258. Photon rest mass energy = 2m0c2 = 1.02 MeV
259. = mve- + mve+
260. λ = =
261. Δp = and Δx = λ
262. (Δp)(Δx) = h
263. (ΔE)(Δt) = h

Chap 19 ATOMIC SPECTRA
264. = R ( - )
265. R =E0 / hc = 1.097 x 107m-1.
266. mvr = nh/2π.
267. h = planks constant = 6.6256 x 10-34 j s.
268. E = hf = En – Ep
269. rn =
270. En = -
271. En = = 2.17 x 10-18 j/ n2 = +13.6 ev/ n2
272. rn = n2 r1 → r1 = 0.53 0A.
273. 1 0A = 10- m
274. 2πr=nλ
275. eV → hfmax = hc/λmin
276. λmin = hc/eV
277. excited state for 10-8 s.
278. metastable state for 10-3 s

Chap 20 NUCLEAR PHYSICS

279. Nuclear size is of the order of 10-14 m.
280. The mass of the nucleus is of the order of 10-27 kg.
281. ½ mv2 = Vq
282. Bqv = mv2/r
283. Bqv = mv2/r → m = Bqr/v
284. ½ mv2 = Vq → v2 = 2Vq/m
285. So m = qr2B2/2V
286. Δm = Zmp + Nmn – M(A,Z)
287. The binding energy in MeV is 931 x Δm.
288. The binding energy per nucleon = Eb/A.
289. 0n1 → 1H1 + -1β0 + antineutrino 12 MIN
290. ΔN/Δt =-λN
291. R =- ΔN/Δt =λN
292. N= N0e-λt
293. 1 Bq = 1 decay per second
294. 1 Ci = 3.70 x 1010 decay/s
295. λT ½ = 0.693
296. The charge on u,t and c, in term of electron is +2/3e.
297. The charge on s,t and b in term of electron is -1/3e.
298. proton =2U→D.
299. neutron=A-Z

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A simple question to put your physics knowledge to test

A satellite is moving in a circular orbit around the earth with a diameter 2R. At a certain point, a rocket fixed to the satellite is fired such that it increases the velocity of the satellite tangentially. The resulting orbit of the satellite would be

A. Same as before
B. Circular orbit with diameter greater than 2R
C. Elliptical orbit with minor axis 2R
D. Elliptical orbit with major axis 2R

Currents induced by changing magnetic f l ux always f l ow in the direction so as to oppose the change in f l ux. That is, if the magnetic f l ux through the circuit is increasing, the induced current produces its own magnetic f l ux in the opposite direction to offset the increase. This situation is shown in Figure 3.6(a), in which the magnet is moving toward the loop. As the leftward f l ux due to the magnet increases, the induced current f l ows in the direction shown, which produces rightward magnetic f l ux that opposes the increased f l ux from the magnet.
The alternative situation is shown in Figure 3.6(b), in which the magnet is moving away from the loop and the leftward f l ux through the circuit is decreasing. In this case, the induced current f l ows in the opposite direc-tion, contributing leftward f l ux to make up for the decreasing f l ux from the magnet.
It is important for you to understand that changing magnetic f l ux induces an electric f i eld whether or not a conducting path exists in which a current may f l ow. Thus, Lenz’s law tells you the direction of the cir-culation of the induced electric f i eld around a specif i ed path even if no conduction current actually f l ows along that path.
Lenz's law

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General Science Ability | Quiz


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