11th And 12th > Physics
UNITS AND DIMENSIONS MCQs
:
C
Volume of sphere (v) = 43πγ3
Percentage error in volume =3 ×Δγγ× 100 = (3 ×0.15.3)× 100
:
D
P=FA=Fl2, So maximum error in pressure (P)
( ΔPP×100)max=ΔFF×100+2Δl1×100
=4%+2×2%=8%
:
A
Dimension of α t = [M0L0T0] ∴[α]=[T−1]
Again [v0α]= [L] so [v0]=[LT−1]
:
C
Percentage error in g=(% error in l) + 2(% error in T)=1%+2(3%)=7%
:
B
Volume V = l × b × t
= 12 × 6 × 2.45 = 176.4 cm3
V = 176.4 ×102 cm3
Since, the minimum number of significant figure is one in breadth, hence volume will also contain only one significant figure. Hence, V = 2 ×102 cm3.
:
C
From the principle of dimensional homogeneity [v] = [αt]⇒[α]=[LT−2]. similarly [b] = [L] and [c] = [T]
:
C
Given equation is dimensionally correct because both sides are dimensionless but numerically wrong because the correct equation is tan θ=v2rg.
:
C
PV = nRT ⇒ R = PVnT = Joulemole×Kelvin=JK−1mol−1
:
A
Formula for viscosity η=πPγ48Vl⇒ V = πPγ48ηl
:
A
By substituting the dimension in T = 2π√R3GM
we get √L3M−1L3T−2×M =T