EXECUTE IMMEDIATE in PL SQL

For the Select statement
DECLARE
L_DEPTNO NUMBER DEFAULT 10;
L_SAL NUMBER;
BEGIN
EXECUTE IMMEDIATE 'select max(sal) from emp
where deptno = :l_deptno'
INTO L_SAL
USING L_DEPTNO;
DBMS_OUTPUT.PUT_LINE(L_SAL);
END;

For the Insert statement
DECLARE
L_ENAME VARCHAR2(20) DEFAULT 'PHANI';
L_EMPNO NUMBER DEFAULT 2;
L_DEPTNO NUMBER DEFAULT 10;
BEGIN
EXECUTE IMMEDIATE 'INSERT INTO EMP(ENAME,EMPNO,DEPTNO) VALUES
(:L_ENAME,:L_EMPNO,:L_DEPTNO)'
USING L_ENAME,
L_EMPNO,
L_DEPTNO;
END;

For the Update Statement
DECLARE
L_ENAME VARCHAR2(20) DEFAULT 'PHANI';
L_EMPNO NUMBER DEFAULT 2;
L_DEPTNO NUMBER DEFAULT 10;
BEGIN
EXECUTE IMMEDIATE 'UPDATE EMP
SET ENAME = ''RAHUL''
WHERE ENAME = :l_ENAME'
USING L_ENAME;
END;