Class 11th

This is a Short Answers Type Questions as classified in NCERT Exemplar

When a trivalent atom is added to the crystal of SiO₂, it substitutes silicon atoms which result in generation of holes. These holes make the crystal conductor of electricity. The overall Crystal is electrically neutral and is called the p-type conductor.

This is a short answer type question as classified in NCERT Exemplar

When the vertical height of the objects is very small as compared to the earth's radius we call the objects small, otherwise it is extended. Building and ponds are small objects and deep lake and ocean are examples of extended objects.

This is a Short Answers Type Questions as classified in NCERT Exemplar

As compared to carbon, silicon is bigger in size and is less electronegative. It shows resistance in forming p−p multiple bonding which is easily done by carbon. Thus, SiO₂ is a 3−D network where each silicon is linked covalently to 4 oxygen atoms while in CO₂, Carbon is linked with two oxygen atoms with double bond in a linear manner.

This is a Short Answers Type Questions as classified in NCERT Exemplar

As we move down the group in group 13 and 14 the participation of s-electrons in bond formation decreases the primary reason behind this is the inert pair effect.

In this the p-electrons take part in bond formation and more energy is required to unpack the valence electrons to make them participate in bonding. Due to this the lower oxidation state of elements becomes stable done the hire oxidation state. As for group 13, +1 oxidation state is more stable than +3 and for group 14, +2 oxidation state is more stable than +4.

This is a long answer type question as classified in NCERT Exemplar

Frictional force f is acting in the opposite direction of F . let the acceleration of centre of mass of disc be a then

F-f=Ma where M is the mass of the disc

$\alpha =\frac{a}{R}$

$\tau =I\alpha$

fR= (1/2 MR²) $\alpha$

so fR= (1/2MR²) (a/R)

Ma=2f

From the above equation

F = F/3

F< $\mu N$ = $\mu Mg$

f/3 < $\mu Mg$

F=3 $\mu Mg$

This is a long answer type question as classified in NCERT Exemplar

area of square = area of rectangular plate

C²=a $*$ b

(a) $\frac{I_{xR}}{I_{xS}}=\frac{b^2}{c^2}$ here bxRxS

(b) $\frac{I_{yR}}{I_{yS}}=\frac{a^2}{c^2}$ here a>c so I_yR>I_yS

(c) I_zR-I_{zS $\propto \left(a^2+b^2-2c^2\right)=a^2+b^2$} +2ab= (a-b)²

(I_zR-I_zS)>0

$\frac{I_{zR}}{I_{zS}}1$

This is a Short Answers Type Questions as classified in NCERT Exemplar

Both BCl₃ and AlCl₃ are electron deficient compounds that are central atom boron and aluminium have incomplete Octet. In each compound, a metal atom is surrounded by six electrons of three covalent bonds with 3 chlorine atoms.

Each chlorine atom has a complete Octet of eight electrons. The electron deficient compounds act as Lewis acid and readily accept two electrons to complete their octet.

This is a long answer type question as classified in NCERT Exemplar

(a) Situation as given below

(b) F' =F=F'' where F' and F'' are external forces through support.

So F_net=O

External torque = F $*3R$ (anticlockwise)

(c) Let w₁ and w₂ be the final angular velocities of smaller and bigger drum in both clockwise and anticlockwise . finally there will be no friction

hence Rw₁=2Rw₂

so $\frac{w_1}{w_2}=2$