1 W.s = ______________ J.

In the given figure, charge Q is placed at the center of a dotted circle. Work done in taking another charge +q from A to B is W_1 and from B to C is W_2 . Which one of the following is correct W_1 > W_2 , W_1 = W_2 and W_1

Ultraviolet light is incident on two photosensitive materials, having work functions W_1 and W_2 , where W_1 > W_2 . In which case will the kinetic energy of emitted electrons be greater? Why?

A lamp consumes 1,000 J of electric energy in 10 s. What is its power ?

Prove that vectors vec u=(a l+a_1l_1) hat i+(a m+a_1m_1) hat j+(a n+a_1n_1) hat k vec v=(b l+b_1l_1) hat i+(b m+b_1m_1) hat j+(b n+b_1n_1) hat k vec w=(c l+c_1l_1) hat i+(c m+c_1m_1) hat j+(c n+c_1n_1) hat k are coplanar.

Calculate the de-Broglie waveelngth of an electron of energy 400 eV.Given,lanck's constant = 6.6 xx 10^(-34) J s, mass of electron = 9.1 xx 10^(31) kg,1 eV = 1.6 xx 10^(-19) J .

The enrgy gap of silicon is 1.14 eV.Find the maximum wavelength ,at which silicon starts energy absorption.Give that 1 eV=1.6 10^(-19) J and h=6.62 xx 10^(-34) J s .

Suppose A_1,A_2….. A_(30) are thirty sets each having 5 elements and B_1B_2…..B_n are n sets each having 3 elements ,Let overset(30)underset(i=1)bigcupA_1=overset(n)underset(j=1)bigcupB_j=s and each element of S belongs to exactly 10 of the A_1 and exactly 9 of the value of n.

If l_(i)^(2)+m_(i)^(2)+n_(i)^(2)=1 , (i=1,2,3) and l_(i)l_(j)+m_(i)m_(j)+n_(i)n_(j)=0,(i ne j,i,j=1,2,3) and Delta=|{:(l_(1),m_(1),n_(1)),(l_(2),m_(2),n_(2)),(l_(3),m_(3),n_(3)):}| then