If potential [in volts][in volts] in a region is expressed as V[x,y,z]=6xy−y+2yz,V[x,y,z]=6xy−y+2yz, the electric field [in N/C][in N/C] at point (1,1,0)(1,1,0) is:
1. | −(3ˆi+5ˆj+3ˆk)−(3^i+5^j+3^k) | 2. | −(6ˆi+5ˆj+2ˆk)−(6^i+5^j+2^k) |
3. | −(2ˆi+3ˆj+ˆk)−(2^i+3^j+^k) | 4. | −(6ˆi+9ˆj+ˆk)−(6^i+9^j+^k) |
A parallel plate air capacitor has capacitance C, the distance of separation between plates is d and potential difference V is applied between the plates. The force of attraction between the plates of the parallel plate air capacitor is:
1. | C2V22d | 2. | CV22d |
3. | CV2d | 4. | C2V22d2 |
A parallel plate air capacitor of capacitance C is connected to a cell of emf V and then disconnected from it. A dielectric slab of dielectric constant K, which can just fill the air gap of the capacitor is now inserted in it. Which of the following is incorrect?
1. | The potential difference between the plates decreases K times. |
2. | The energy stored in the capacitor decreases K times. |
3. | The change in energy stored is 12CV2(1K−1) |
4. | The charge on the capacitor is not conserved. |
Two thin dielectric slabs of dielectric constants K1 and K2 (K1<K2) are inserted between plates of a parallel plate capacitor, as shown in the figure. The variation of electric field ′E′ between the plates with distance ′d′ as measured from the plate P is correctly shown by:
1. | 2. | ||
3. | 4. |
A conducting sphere of the radius R is given a charge Q. The electric potential and the electric field at the centre of the sphere respectively are:
1. | Q4πε0R2 | zero and2. | Q4πε0R and zero |
3. | Q4πε0R and Q4πε0R2 | 4. | both are zero |
In a region, the potential is represented by V=(x,y,z)=6x−8xy−8y+6yz, where V is in volts and x,y,z are in meters. The electric force experienced by a charge of 2 coulomb situated at a point (1,1,1) is:
1. 6√5 N
2. 30 N
3. 24 N
4. 4√35 N
A, B and C are three points in a uniform electric field. The electric potential is:
1. | B | maximum at
2. | C | maximum at
3. | A,B and C | same at all the three points
4. | A | maximum at
An electric dipole of moment p is placed in an electric field of intensity E. The dipole acquires a position such that the axis of the dipole makes an angle θ with the direction of the field. Assuming that the potential energy of the dipole to be zero when θ=90∘, the torque and the potential energy of the dipole will respectively be:
1. pEsinθ, −pEcosθ
2. pEsinθ, −2pEcosθ
3. pEsinθ, 2pEcosθ
4. pEcosθ, −pEsinθ
Four-point charges −Q,−q,2q and 2Q are placed, one at each corner of the square. The relation between Q and q for which the potential at the center of the square is zero is:
1. | Q=−q | 2. | Q=−2q |
3. | Q=q | 4. | Q=2q |
Two metallic spheres of radii 1 cm and 3 cm are given charges of −1×10−2 C and 5×10−2 C, respectively. If these are connected by a conducting wire, then the final charge on the bigger sphere is:
1. 3×10−2 C
2. 4×10−2 C
3. 1×10−2 C
4. 2×10−2 C