Nội dung text IIT-JAM QM DPP Sheet 06.pdf
2 North Delhi : 56-58, First Floor, Mall Road, G.T.B. Nagar (Near Metro Gate No. 3), Delhi-09, Ph: 011-41420035 South Delhi : 28-A/11, Jia Sarai, Near-IIT Metro Station, New Delhi-16, Ph : 011-26851008, 26861009 6. If 2 exp ax an eigenfunction of the operator 2 2 2 d x dx , then the constant B and cirresponding eigen- value are respectively (a) 2 B a a 2 , 2 (b) 2 B a a 4 , 2 (c) 2 B a a 4 , 2 (d) 2 B a a 2 , 2 7. The operator d d x x dx dx is equivalent to (a) 2 2 2 1 d d x dx dx (b) 2 2 2 1 d d x dx dx (c) 2 2 2 2 1 d d x x dx dx (d) 2 2 2 1 d x dx 8. A particle is subjected to the potential energy 1 2 2 V x kx . At a particular time, it has the wave function 2 2 x a/ x Axe . If the particle has a definite total mechanical energy, then the possible value of ‘a’ is (a) 1/4 2 4 mk (b) 1/2 2 4 mk (c) 1/2 4 mk (d) 1/4 4 mk 9. Consider a one-dimensional particle which moves along the x-axis and it’s Hamiltonian is given as 2 2 2 ˆ 16 ˆ d H x dx where is a real constant having the dimensions of energy. If the particle is in an energy eigenstate having wave function 2 2 2 x x xe , then the energy of the particle will be (a) 2 (b) 4 (c) 8 (d) 12 10. Consider a physical sysytem whose Hamiltonian H and initial state 0 are given by 0 0 0 1 1 0 0 ; 1 5 0 0 1 i i H i i where has the dimension of energy. If we measure the energy of the system, then the probability of getting the energy is (a) 0.4 (b) 0.2 (c) 0.6 (d) 0 11. If the function 1 2 exp 2 f x x is an eigenfunction of the operator 2 2 2 ˆ d A x dx , then the corresponding eigenvalue will be (a) 1 (b) -1 (c) 2 (d) -2 12. Suppose a particle of mass m is confined within the region 0 x L and moving freely in it. Which of the following can possibly be the eigenstate of the Hamiltonian operator for the system? (n is a positive integer) (a) exp n x L (b) exp n x L (c) sin n x L (d) cos n x L
3 North Delhi : 56-58, First Floor, Mall Road, G.T.B. Nagar (Near Metro Gate No. 3), Delhi-09, Ph: 011-41420035 South Delhi : 28-A/11, Jia Sarai, Near-IIT Metro Station, New Delhi-16, Ph : 011-26851008, 26861009 13. The value of the commutator bracket 2 2 ˆ ˆ , x x p (where xˆ and ˆ x p are position and linear momentum operators respectively) is (a) 2i xp p x ˆˆ ˆ ˆ x x (b) 2i xp p x ˆˆ ˆ ˆ x x (c) 4 ˆˆ x i xp (d) 4 ˆ ˆ x i p x 14. For a quantum mechanical system in 1-D, the commutator bracket ˆ x x H ˆ ˆ , , (where xˆ and Hˆ are position and Hamiltonian operators respectively) is (a) 2 i m (b) 2 i m (c) 2 m (d) 2 m 15. The value of the commutator bracket ˆ , F x x is (a) F x ˆ (b) ˆ I (c) - ˆ I (d) Fˆ x 16. Let xˆ and ˆ x p denote the coordinate and momentum operators satisfying the canonical commutation relation x p i ˆ ˆ , x in natural units 1. Then the commutator x p ˆ ˆ ,sin x is (a) cos ˆ x i p (b) cos ˆ x i p (c) sin ˆ x i p (d) sin ˆ x i p 17. The value of the commutator brackets xp p x p ˆˆ ˆ ˆ ˆ x x x , and xp p x x ˆˆ ˆ ˆ ˆ x x , (where xˆ and ˆ x p are position and linear momentum operators respectively) are (a) 2 , 2 ˆ ˆ x i p i x (b) 2 , 2 ˆ ˆ x i p i x (c) 2 , 2 ˆ ˆ x i p i x (d) 2 , 2 ˆ ˆ x i p i x 18. The value of the commutator bracket 2 2 ˆ xˆ, x is (a) ˆ 2 x (b) ˆ 2 x (c) ˆ x (d) ˆ x 19. A and B ˆ ˆ are two quantum mechanical operators. If ˆ ˆ A B, stands for the commutator of Aˆ and Bˆ , then ˆ ˆ ˆ ˆ A B B A , , , is equal to (a) ABAB BABA ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ (b) A AB BA B BA AB ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ (c) zero (d) 2 ˆ ˆ A B, 20. x and p are two operators which satisfy x p i , . the operators X and Y are defined as X x p Y x p cos sin and sin cos where is a real parameter. Then X Y, equals to (a) 1 (b) –1 (c) i (d) –i